Immune checkpoint inhibitors (ICIs), including anti-programmed death-1 (PD-1), anti-programmed death ligand-1 (PD-L1), and anti-cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4)antibodies have improved overall survival (OS) of patients with multiple types of malignancies, including melanoma, renal cancer, and non-small cell lung cancer (1, 2). The gene discussed is CTLA4; the disease is melanoma.