Study of Alterations in Tumor Metabolism Associated With the Development of Immunotherapy Resistance in Melanoma

This study is examining how the metabolism (energy use) of melanoma tumors changes when patients receive immunotherapy, and whether those changes help explain why some tumors eventually stop responding to treatment. Understanding this could help doctors find ways to prevent or overcome immunotherapy resistance. **You may be eligible if...** - You are 18 years or older - You have stage III (unresectable) or stage IV skin melanoma that has spread, and you are about to start immunotherapy for the first time - You have good general health (Performance Status 0–1) - Your BRAF gene status has been tested (any result is acceptable) - Women of childbearing age are using effective contraception **You may NOT be eligible if...** - You are pregnant or breastfeeding - You have ocular (eye) or mucosal melanoma - You are being treated with targeted therapies instead of immunotherapy - You have HIV, hepatitis B or C, or an active autoimmune disease (like Crohn's, lupus, or Guillain-Barré syndrome) - You are a minor or legally under guardianship Talk to your doctor to see if this trial is right for you.