Immunotherapy is a type of cancer treatment that uses substances made by the body or in a laboratory to boost the immune system and help the body find and destroy cancer cells. It works by helping the immune system recognize and attack cancer cells. Immunotherapy can be used alone or in combination with chemotherapy and/or other cancer treatments. There are different types of immunotherapy, including monoclonal antibodies, checkpoint inhibitors, vaccines, and adoptive cell therapy. Different types of immunotherapy work in different ways, some help the immune system stop or slow the growth of cancer cells, while others help the immune system destroy cancer cells or stop the cancer from spreading to other parts of the body. Immunotherapy is an important approach as cancer researchers continue to look for new cancer treatments. Immunotherapy works better for some types of cancer than for others, and it is a standard treatment for some types of cancer. If immunotherapy is a cancer treatment option for you, you should consider asking your health care team questions about it.