Several predictors of the response to programmed death-1 (PD-1) blockade have been reported, such as the presence of tumor-infiltrating T cells, high programmed death-ligand 1 (PD-L1) expression in biopsies, microsatellite instability (MSI), KEAP1 and STK11 mutations test and the tumor mutational burden (TMB)1–4. The gene discussed is KEAP1; the disease is neoplasm.