We found anti-PD-1 mAbs are the ICIs more often associated (when compared with CTLA-4 Ab) with autoimmune thyroiditis (37 vs 6 as monotherapy), primary hypothyroidism (15 vs 2 as monotherapy), hyperthyroidism progressing to hypothyroidism (30 vs 2 as monotherapy) and type 1 diabetes mellitus (45 vs 1 as monotherapy). This evidence concerns the gene CTLA4 and hypothyroidism.