Understanding Cancer Immunotherapy

Immunotherapies are used to treat more than 35 cancer types, including melanoma, lung, bladder, kidney, breast, and colorectal cancers. Researchers are studying immunotherapy for many more cancer types and treatment settings in clinical trials.

Chemotherapy kills fast-dividing cells, including cancer cells and some healthy cells. Immunotherapy helps your immune system recognize and attack cancer cells. Both treatments can be given in different ways, depending on the specific drug and treatment plan. Learn more about differences between chemotherapy and immunotherapy.

The main types of immunotherapies include immune checkpoint inhibitors (ICIs), bispecific antibodies, cell and gene therapies, oncolytic viruses, cancer vaccines, and cytokines and other immune-stimulating therapies (also called non-ICI-immunomodulators). Learn about each type.

Cancer immunology, also called immuno-oncology, is the study of how the immune system interacts with cancer and how that knowledge can help prevent, detect, and treat cancer.

Your care team will consider your cancer type and stage, biomarkers or genetic changes, prior treatments, overall health, and immune system function before recommending immunotherapy.

Many immunotherapies are given through an IV in a doctor’s office, outpatient clinic, hospital, or cancer center. Some are given as injections, pills, skin creams, or treatments placed directly into the bladder (intravesical).

Immunotherapy may be used at many stages of cancer, depending on the type and treatment approval. It’s often used for advanced or metastatic cancer, but some immunotherapies are also used before surgery (neoadjuvant therapy), after therapy (adjuvant therapy), or with other treatments to help reduce the risk of cancer returning.

Common side effects may include fatigue, skin changes, diarrhea, cough, or inflammation. More serious side effects can occur but are often treatable when caught early. Contact your health care team right away if you notice new or worsening symptoms. Learn more about side effects.

If you are currently experiencing side effects or unusual symptoms, contact your health care team immediately.

Your health care team will monitor your progress with checkups, lab tests, and imaging scans. Sometimes tumors may look larger before shrinking, a temporary effect called pseudoprogression. Your doctor can help interpret changes over time.

Immunotherapy can be highly effective for some people, but it does not work for everyone. For some, it may lead to long-term remission. For others, it may help manage cancer, extend life, or improve quality of life.

Sometimes, but these situations require special care. People with mild or well-controlled autoimmune conditions may be able to receive immunotherapy with close monitoring. For organ transplant recipients, immunotherapy can increase the risk of transplant rejection, so it is considered only in select cases with specialist guidance.

Costs vary widely based on the treatment, schedule, insurance coverage, and care setting. Immunotherapy can be expensive, but many insurance plans cover approved treatments. Your health care team, insurance provider, hospital financial counselor, or trusted organizations such as CancerCare, Patient Advocate Foundation, or HealthWell Foundation may help you understand costs and support options.

Early immunotherapy experiments date back to the 1890s, when Dr. William B. Coley used bacteria to stimulate the immune system. Modern immunotherapy began advancing rapidly in the 1990s and is now part of standard care for many cancers. Explore CRI’s timeline of immunotherapy milestones.

Cancer develops when abnormal cells grow out of control. The immune system can often find and destroy abnormal cells, but some cancers hide from immune attack or suppress immune activity. Immunotherapies help restore the immune system’s ability to recognize and fight cancer.

For more than 70 years, the Cancer Research Institute (CRI) has funded research into how the immune system can fight cancer, from laboratory discoveries to clinical trials. Explore CRI-funded research.

CRI regularly publishes patient education resources, research updates, and stories about progress in cancer immunotherapy. Sign up for updates and explore our patient resources to keep learning.