ICPI-related hypophysitis is frequently (up to 17% of cases) associated with ipilimumab, an anti-cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) antibody, but hypophysitis is an extremely rare event (< 1%) in patients treated with other ICPIs, such as nivolumab [3]. This evidence concerns the gene CTLA4 and hypophysitis.