The following keywords or corresponding Medical Subject Headings (MeSH) terms were used: “Immune checkpoint inhibitor,” “CTLA-4,” “Ipilimumab,” “Tremelimumab,” “PD-1,” “Nivolumab,” “Pembrolizumab,” “Cemiplimab,” “PD-L1,” “Atezolizumab,” “Durvalumab,” “Avelumab,” “Hypophysitis,” “Hypopituitarism,” “Pituitary dysfunction.” The gene discussed is PDCD1; the disease is hypopituitarism.