Nivolumab, an anti-programmed death-1 (PD-1) antibody, and ipilimumab, an anti-cytotoxic T-lymphocyte associated-protein 4 (CTLA-4) antibody, have led to improvements in survival when used in stage III and IV melanoma patients (Wolchok et al., 2017). The gene discussed is CTLA4; the disease is melanoma.