It has been reported that thyroid function in patients with painless thyroiditis, a type of destructive thyroiditis seen in patients with Hashimoto thyroiditis, mostly became normal after transient thyrotoxicosis.20 These data suggest that the thyroid destruction induced by anti-PD-1 antibodies is much more severe than that seen in painless thyroiditis. Here, PDCD1 is linked to Hashimoto thyroiditis.