Primary hypothyroidism occurs in 6%–9% of patients treated with anti-PD-1 and/or anti-PD-L1, 4%–9% of patients treated with anti-CTLA-4, and approximately 16% of patients treated with anti-PD-1 (L)-1 and anti-CTLA-4 (91). Here, CTLA4 is linked to Primary hypothyroidism.