Immunotherapy is a type of medical treatment that harnesses the power of the body's immune system to fight diseases such as cancer. In recent years, immunotherapy has become an important area of research and has shown tremendous promise as a treatment option for many types of cancer. The immune system is a complex network of cells, tissues, and organs that work together to protect the body from foreign invaders, such as viruses and bacteria. Cancer cells, however, can evade the immune system and multiply unchecked. Immunotherapy aims to boost the immune system's ability to recognize and attack cancer cells. CAR T-cell therapy, this type of immunotherapy involves removing immune cells (T-cells) from the patient, modifying them in the lab to better recognize and attack cancer cells, and then returning them to the patient. Vaccines, cancer vaccines are designed to stimulate the immune system to attack cancer cells. Unlike traditional vaccines, which protect against infections, cancer vaccines are used to treat existing cancer. Immunotherapy has shown great promise as a treatment option for many types of cancer, including melanoma, lung cancer, kidney cancer, and bladder cancer. In some cases, immunotherapy has even been able to shrink tumors that have not responded to other treatments. In conclusion, immunotherapy is a rapidly growing area of cancer treatment that has shown tremendous promise in recent years. By harnessing the power of the immune system, immunotherapy offers a new way to fight cancer and improve outcomes for patients. However, more research is needed to fully understand the potential of immunotherapy and to determine how best to use it to treat cancer.