context: Compared with many run-of-the-mill infections or illnesses, cancer is an incredibly complex disease. To boost the odds of a cure, or long-term remission, cancer doctors often combine treatments. Sometimes, one type of treatment can help another work better, or two drugs make each other more potent. In the case of immunotherapies -- treatments that use your body's own immune system against a cancer -- combination therapies are a common approach since many of the therapies are new. Pairing them, or adding a new immunotherapy to a course of radiation, hormone therapy, or chemotherapy, has worked with more than one type of cancer. Doctors may combine two immunotherapies that work in different ways and have been effective. Some of these treatments rev up your immune system, blocking brakes that a cancer has put on immune cells. Others teach it to spot tumor cells as invaders, among other methods. Combining immunotherapy drugs that work on many fronts, researchers think, can make your immune system even more powerful. Already, the FDA has approved the immunotherapies nivolumab ( Opdivo) plus ipilimumab ( Yervoy) for combined use with certain types of metastatic melanoma, advanced colorectal cancer, and advanced kidney cancer. Other combination therapies are approved for certain cancers. The drugs work better together than either one does alone. Studies on other combination immunotherapies are being done. There are good reasons for doctors to be excited about pairing immunotherapy drugs with radiation that shrinks tumors and kills cancer cells: Radiation affects some immune cells. Immunotherapy can reverse this damage. Studies show that radiation can make cancer cells vulnerable to attack by the immune system. Combining radiation with immunotherapy drugs has been studied in breast cancer, lung cancer, renal cell carcinoma, prostate cancer, melanoma, uterine cancer, and sarcoma. Researchers think that similar to radiation, chemotherapy may make some tumors more likely to respond to immunotherapy. Chemotherapy is used along with two types of immune cell gene therapy: CAR T-cell therapy and TCR therapy. CAR T-cell therapy has been approved to treat two types of blood cancer, while TCR therapy is still in the research stages. Both treatments involve âreprogrammingâ immune cells called T cells to fight cancer better. Doctors typically recommend a course of chemotherapy before the re-engineered T cells are put in your bloodstream to cut down the number of other immune cells in your body. This makes it easier for the T cells to seek out and destroy cancer cells. Immunotherapy drugs such as nivolumab are also being combined with different chemotherapies to try to make it work even better. Nivolumab is a targeted therapy medication that's used to treat certain types of melanoma and Hodgkin's lymphoma, as well as lung, kidney, bladder, head and neck, colorectal, and liver cancers. It's designed to boost the T cells' attack on cancer cells. In addition to the classic cancer treatments -- radiation, surgery, and chemotherapy -- scientists have recently developed targeted therapies for a number of tumor types. Rather than killing all cells that, like cancer cells, quickly divide, these drugs home in on tumor cells with certain changes or molecules. Because many targeted therapies can change the way a tumor interacts with your immune system, weakening the cancer, researchers are now studying whether adding immunotherapy to targeted drugs can make them even more powerful. It depends on what cancer type you have and what drugs your doctor recommends. Because you'll be getting more than one treatment -- some of which may be given through an IV or require a hospital stay -- you may need to schedule extra appointments. Some combinations may require you to take two drugs at the same time. Or you may need to take two drugs in sequence if one is used to weaken your tumor and make it more likely to respond to the second.