In the landmark CheckMate 067 trial evaluating combination ICI (cICI), the incidence of hypophysitis reported with ipilimumab and nivolumab combination, nivolumab, and ipilimumab was 7%, 1%, and 4%, respectively, suggesting that anti-CTLA-4 therapy is the major driver of this immune-related adverse event (irAE) (5, 6). The gene discussed is CTLA4; the disease is hypophysitis.