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, COL17A1 is linked to myositis disease.