Immune checkpoint inhibitors (ICIs) such as ipilimumab (a cytotoxic T-lymphocyte-associated protein 4 or CTLA-4 inhibitor) and nivolumab (a programmed cell death protein 1 or PD-1 inhibitor) are effective therapies for advanced melanoma but are associated with immune-related adverse events (irAEs), including endocrinopathies, many of which are irreversible [1,2]. The gene discussed is CTLA4; the disease is melanoma.