Purpose

This phase II/III trial studies the side effects of nivolumab and ipilimumab when given together with or without sargramostim and to see how well they work in treating patients with stage III-IV melanoma that cannot be removed by surgery (unresectable) and that may have spread from where it first started to nearby tissue, lymph nodes, or distant parts of the body (advanced). Immunotherapy with monoclonal antibodies, such as ipilimumab and nivolumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Colony-stimulating factors, such as sargramostim, may increase the production of white blood cells. It is not yet known whether nivolumab and ipilimumab are more effective with or without sargramostim in treating patients with melanoma.