Deucravacitinib (BMS-986165) is a highly selective, orally bioavailable allosteric TYK2 inhibitor for the treatment of autoimmune diseases, which selectively binds to TYK2 pseudokinase (JH2) domain (IC50=1.0 nM) and blocks receptor-mediated Tyk2 activation by stabilizing the regulatory JH2 domain. Deucravacitinib inhibits IL-12/23 and type I IFN pathways. Deucravacitinib, the FDA's world first de novo deuterium, is available for study in moderate to severe plaque psoriasis.