It has been reported that the incidence of endocrine-related irAEs is increased when multiple immune checkpoint inhibitors are used compared to monotherapy (7) and that the incidence of hypothyroidism with immune checkpoint inhibitors is higher with CTLA-4 inhibitors, PD-L1 inhibitors, nivolumab, pembrolizumab, and CTLA/4/PD-1 inhibitor combination therapy, in this order. Here, PDCD1 is linked to hypothyroidism.