At a press conference today, former President Jimmy Carter revealed the ways he is tackling the melanoma cancer that has spread to his brain and liver: He'll receive radiation, as well as another lesser-known treatment called immunotherapy. Up until now, most cancer patients only had a few options. They could get chemotherapy or radiation that kills cancerous cells and stops them from dividing, or surgery to cut out the disease. Yet the success rate of these options is far from perfect. Now a new kind of cancer treatment has come into play: immunotherapies. These treatments, which include Carter's infusion called...