Various autoantibodies have been suggested as potential biomarkers of irAEs, such as myositis (anti‐acetylcholine receptor antibodies),27 thyroiditis (antithyroglobulin, antithyroid peroxidase),23, 28 hypophyitis (anti‐GNAL, anti‐ITM28),29 pneumonitis (anti‐CD74),29 or skin reactions (anti‐BP180).30 Here, CD74 is linked to skin reaction.