CTLA4 and melanoma: Previous studies have shown an increase in the number of circulating eosinophils and in the infiltration of eosinophils in the dermis in patients who develop cutaneous irAEs while receiving anti-CTLA-4 therapy29, and a significant correlation between baseline absolute and relative eosinophil counts and the occurrence of endocrine irAEs at 1 month in patients with melanoma treated with anti-PD-1 antibodies30.