Immunotherapy treating melanoma is comprised of programmed cell death protein 1 (PD-1) inhibitor monoclonal antibodies (e.g., nivolumab and pembrolizumab), programmed death-ligand (PD-L1) inhibitor (e.g., atezolizumab), cytotoxic T-lymphocyte associated molecule-4 (CTLA-4) inhibitor (e.g., ipilimumab), a combination of ipilimumab and nivolumab, interleukin-2 (IL-2), virus therapy (e.g., talimogene laherparepvec), and interferon (e.g., high-dose interferon alfa-2b and pegylated interferon alfa-2b). The gene discussed is PDCD1; the disease is melanoma.