Immunotherapy stimulates the body’s immune system to fight cancer. As tumor cells grow, they begin to produce proteins that shield themselves from a person’s immune system. Immunotherapy drugs are able to break that shield and stimulate the body’s immune system to attack the tumor cells. Treatment for melanoma, an often deadly form of skin cancer, has been revolutionized by the introduction of new immunotherapy drugs. Cleveland Clinic is researching how this immunotherapy can help patients with other difficult to treat cancers, including bladder, brain, lung and kidney cancer.