In our cohort, patients treated with anti-CTLA4 comprised the majority (16/97 or 16.4%) of those who developed hypophysitis, whether they are treated concurrently or sequentially with anti-PD1, or if they received anti-CTLA4 monotherapy, compared with 6/168 (3.6%) of patients receiving anti-PD1/PDL1 therapy exclusively. This evidence concerns the gene CTLA4 and hypophysitis.