CTLA4 and cancer: While anti-programmed cell death protein 1 (anti-PD-1) and anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) antibodies have been extensively used to target immune checkpoints in many cancers, their use in pituitary tumors has only just commenced, with a case of a corticotroph carcinoma bearing alkylator-induced hypermutations showing a partial response on combined nivolumab and ipilimumab [25] (Table 1).