In summary, this study utilized ex vivo HS tissue biopsies to elucidate the role of the IL‐17A pathway in the pathogenesis of HS, and clinically validated the IL‐17A pathway in moderate‐to‐severe HS in a proof‐of‐concept Phase II clinical study using the anti‐IL‐17A antibody CJM112. Here, IL17A is linked to histiocytic sarcoma.