Immune checkpoint inhibitors (ICIs), such as anti-programmed death receptor 1 (anti-PD-1), anti-programmed death-ligand 1 (anti-PD-L1), and anti-cytotoxic T-lymphocyte-associated protein-4 (anti-CTLA-4), constitute the primary approach to immunotherapy, achieving a considerable effect in patient with non-small cell lung cancer (NSCLC) or malignant melanoma among other cancer patient (6, 7). The gene discussed is CTLA4; the disease is cancer.