Currently, anti–PD-1/PD-L1 checkpoint antibodies are approved by the FDA to treat melanoma, non–small cell lung cancer (NSCLC), Hodgkin lymphoma, Merkel cell carcinoma, renal cell carcinoma (RCC), urothelial carcinoma, and head and neck cancers (Boutros et al., 2016; Topalian et al., 2012). The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.