What is immunotherapy and how does it work?

Immunotherapy is a type of treatment that harnesses the body's immune system to combat cancer. This video explainer from the American Cancer Society discusses various types of immunotherapies and their roles in targeting cancer cells. Still a new and quickly evoliving field, immunotherapy represents a significant advancement in cancer treatment and offers new options for patients.

A new type of immunotherapy focuses on healthy cells hijacked by tumors

Purdue University scientists are at work on a new cancer treatment that attacks immune system cells that feed and protect cancer cells rather than attacking them. The immunotherapy process promises to become a universal treatment for solid tumors. Thus far, the treatment has been tested and shown to work on human tumor cells in the laboratory and animal models.

Frequently asked questions on immunotherapy

The Cancer Research Institute takes a close look at immunotherapy and its potential for treating cancer. Immunotherapy teaches the patient's own immune system to recognize and fight cancer cells. It's especially promising as an alternative for cancers that resist chemotherapy and radiation treatment. Have all your questions about the process and its promise here.

Teaching immune cells to fight cancer

CAR T-cell therapy is a type of immunotherapy, which involves strengthening the immune system to attack cancer cells. Patient T cells, which manage immune responses and are responsible for killing pathogen-infected cells, are collected and re-engineered to produce surface-level proteins called chimeric antigen receptors. These CARs, now able to bind to specific proteins on cancer cell surfaces, are multiplied into the millions and infused back into the patient.

The difference between standard cancer treatments and emerging immunotherapies

If you've ever wondered what the difference was between immunotherapy and chemotherapy, this short video takes you through the steps. Briefly, chemotherapy attacks cancer in tumor cells directly, while immunotherapy encourages your immune system to fight it. There's more to it than that, but this delightful two-and-a-half-minute video provides a good primer.

The immune system is in a constant fight to detect and eliminate cellular mutations.

How is immunotherapy used to fight cancer?

The Dana-Farber Cancer Institute provides a delightful Science Illustrated animation explaining PD-1/PD-L1 immunotherapy and how it fights cancer. Briefly, the treatment helps T-cells recognize cancerous cells that would ordinarily be "disguised" by proteins and attack. The fight is made more fair and effective by immunotherapy and similar cancer treatments.

See how CAR-T cell therapy works to help fight cancer

Short for chimeric antigen receptor T-cell therapy, CAR-T Cell Therapy helps augment the body's own ability to attack cancer cells. It's a cell-based gene therapy that alters the genes in a person's T cells—which are a type of immune cell—to help them beat back cancerous growths.

Why CAR-T therapy has become one of the main focus areas for autoimmune diseases

The therapy, originally targeting cancer, involves taking a patient's own T cells, genetically reprogramming them to recognize and attack a specific target and then infusing them back into patients. For autoimmune diseases, the therapy instead programs them to target immune cells that are causing problems, restoring immune system tolerance.

Chemotherapy is a cocktail of powerful drugs that slows cancer by interfering with cell division.

Cancer is a group of diseases characterized by the uncontrolled growth of abnormal, mutated cells that can spread throughout the body.

What is cancer bioengineering?

While new treatments for cancer are under continuous development, researchers are increasingly using engineering principles to find wholly new strategies to combat the disease. Directions include nanoparticle drug delivery, advanced imaging tools, developing new materials to interact with cells, tissue engineering, robotic surgeries, and more. Such interdisciplinary efforts are expected to unlock new tools and therapies beyond traditional drug formulation.

How Nobel Prize-winning research unraveled why the immune system doesn't always attack itself

The 2025 Nobel Prize was awarded to scientists who discovered how immune system soldiers are typically stopped from attacking healthy tissue. The work furthered autoimmune understanding and cancer therapies.

Specific gut microbiome 'fingerprints' are associated with cancer recurrence, with up to 94% accuracy.

Explore the National Cancer Institute's archive on cancer treatments, including complementary and alternative medicine.

Learn how monoclonal antibodies, which mimic the body's antibodies, can fight diseases like Ebola.

Combining two cancer drugs increased the life space of mice by 30%

A study shows trametinib and rapamycin, two drugs used for cancer treatment in humans, increased mouse lifespan when used together. The medications delayed the onset of cancer and reduced chronic inflammation, results that will be explored in future research.

mRNA vaccines alter immune response, not DNA, to combat diseases like cancer.

There are hundreds of subtypes of cancer, making a universal cure nearly impossible.

Tumor genetic profiling can lead to targeted treatments

Genetic profiling of tumors—based on a sample from the tumor, a patient's blood, or both—can help clinicians determine if targeted therapies known to block the growth of certain types of tumors would be appropriate for specific patients.

The immune system fights tattoos

Our skin is a fascinating organ that wants nothing more than to protect our bodies from the outside world. Tattoos penetrate that protective wall to inject ink directly into the sensitive, immunologically rich layer of skin known as the dermis.

How does cancer actually kill someone?

While the emotional and physical tolls of cancer are often clear, the innerworkings of how cancer kills can be confusing — and terrifying to discuss. Here, oncologists explain how cancer can progress.

Chronic inflammation can cause cellular damage and could lead to cancer

Over time, this cellular defense system can inadvertently damage cells and tissues when it's in this heightened alarm mode over a prolonged period. This occurs because, when immune cells are sent somewhere without a true target, they may attack healthy cells and tissues.

Early research suggests CAR-T therapy might treat scleroderma, reducing skin thickening

Clinical data from a couple patients in 2025 indicated that one experimental CAR-T therapy called rese-cel was able to genetically reprogram T cells to eliminate certain problematic immune B cells that were causing the condition. The therapy reduced skin thickening and allowed the patients to halt using immunosuppressive medications and steroids.

Cancer is typically broken down into four stages influenced by tumor size, the presence of cancerous cells in the lymph nodes, and the extent to which the malignancy has spread to other organs in the body.

How does cancer spread through the body?

Cancer usually begins with one tumor, but it can spread to other organs if not removed. This video breaks down how cancer moves to these new areas and why some organs are more likely to get infected than others.

Immunosuppressants enable organ transplants, but come with severe side effects

This drug cocktail helps to lower your body's natural response to attack a transplanted organ. Such medications usually need to be taken for a lifetime after receiving an organ and can come with serious side effects including high blood pressure, diabetes, increased risk of some cancers, and high cholesterol, among others.

An interactive dive into the immune system

Our bodies are equipped with an incredible system able to fight off invasive pathogens to protect us from illness. The complicated system includes lymph nodes, the spleen, bone marrow, and even the tonsils. But this same system can turn against itself, a condition known as autoimmune disorders. Follow along with this thorough, engaging explainer on the human body's defense system.

Large animals like giraffes and elephants have evolved unique cancer defenses.

How Gleevec transformed leukemia treatment and cancer research

An outline of the discovery of imatinib (Gleevec), a ground-breaking drug that transformed the treatment of chronic myelogenous leukemia and sparked the beginning of precision medicine.

Cells become cancerous if checkpoints in the cell cycle are damaged

Before cells divide, a protein called p53 can halt the cell cycle if damaged DNA is identified, preventing the fault from propagating to daughter cells. If p53 and other tumor-suppressing molecules cannot function due to mutations or other instabilities, damage can accumulate over successive generations until nothing stops cells from dividing uncontrollably, creating tumors.

How to think yourself into health

Can the right thoughts lead to a stronger immune system? Neuroimmunologists like Hai Qi study how drugs targeting the brain, as well as thought exercises, can prompt stronger immune responses to infection. This six-minute video investigates the radical claims.

Autoimmunity is when the body attacks itself, causing inflammation

Inflammation is the body's way of healing itself, and acute inflammation saves our lives when we have injuries or infections. It increases blood flow to the affected areas to bring immune cells to fight off invaders. This often results in short-term swelling, redness, and pain.

A clinical trial is underway in 2026 to help kidney transplant recipients avoid a lifetime of immunosuppressing drugs

This later-stage clinical trial, in Chicago and Taiwan, evaluates the efficacy and safety of a new cellular therapy that may be swapped in for immunosuppressing drugs among kidney transplant recipients. The study randomizes people to either receive standard immunosuppressants or this cellular therapy and fewer immunosuppressants. It only includes kidney transplant recipients receiving organs from live donors so transplant surgery timing won't hinge on the unpredictable schedule of performing surgery and follow-up care when a donor dies.

Metastasis: When cancer cells begin to travel through the body

Metastatic cancer starts in one part of the body and moves to another over time. This is known as metastasis. Such cancers are much more harmful since they attack multiple parts of the body, adapting new metabolic changes to suit the various environments found throughout a body.

Advanced drugs are closing in on cancer's deadliest mutations

The protein KRAS, mutated in many cancers, was deemed ‘undruggable’. Now scientists are hoping to save lives with a batch of new compounds that target it.

Using deep learning to analyze tumors

The explosive growth of life sciences data is driving artificial intelligence methods to gain traction in biology and medicine — including cancer research.

How autoimmune diseases, which attack your own tissues and cells, work in the body

These diseases remain some of medicine's thorniest problems because the immune system can mistakenly attack almost any tissue in the body, resulting in myriad diseases, including lupus (numerous tissues affected), Hashimoto's (thyroid), and MS (the nervous system).

Gene therapy can occur inside the body, but it can also be completed outside the body—with scientists treating cells in the lab, and then those corrected cells are transplanted back into the body.