The incidence of severe neurotoxicities of anti-PD-1 and anti-PD-L1 antibodies was very rare (reported to be < 1%) compared with other iAE, including dermatologic toxicities (34–39%), diarrhea/colitis (1–3%), hypophysitis (1–6%), hepatic toxicities (5% or less), and pneumonitis (< 10%) [5, 6]. Here, PDCD1 is linked to hypophysitis.