CTLA4 and hypothyroidism: Thyroiditis and hypothyroidism (occasionally hyperthyroidism) are among the most frequent endocrine irAEs with ICIs; meta-analyses report hypothyroidism ≈ 3.8% with CTLA-4 monotherapy (ipilimumab), ≈7% with PD-1 monotherapy (6.5% with nivolumab; 7.9% with pembrolizumab), and 13.2% with combined regimens; the pooled overall incidence across regimens is 6.6% [8,9].