Several agents, including interferon-alpha, high-dose interleukin-2 (IL-2), and checkpoint inhibitors targeting the cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed cell death 1 (PD-1) receptors have been approved by the FDA for the treatment of metastatic melanoma [12]. This evidence concerns the gene IL2 and metastatic melanoma.