Abstract: Immune checkpoint inhibitors (ICIs) are novel drugs used in recent years for cancer treatment, and they have brought new hope for several patients. Currently, the targets of ICIS are programmed cell death receptor-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte antigen-4 (CTLA-4). With the increasing use of ICIs, more immune-related adverse effects (irAEs) have been reported, and the involvement of endocrine glands is particularly common. The pathogenesis of these irAEs is unknown, and their clinical manifestations are complex; thus, clinicians need to pay more attention to such irAEs. In this review, the mechanism of ICIs and research progress of endocrine side effects are assessed, and pathogenesis, epidemiology, and clinical manifestations are also summarized.