Inclusion Criteria - Participants must have stable plaque psoriasis for 6 months or more prior to Screening. - Participants must have moderate to severe psoriasis defined by:. i) Psoriasis Area and Severity Index (PASI) ≥ 12, at screening visit and Day 1. ii) Static Physician's Global Assessment (sPGA) ≥ 3, at screening visit and Day 1. iii) Body Surface Area (BSA) ≥ 10% involvement, at screening visit and Day 1. - A female (as assigned at birth) participant is eligible to participate if she is not pregnant or breastfeeding, and at least 1 of the following conditions applies:. i) Is not an individual of childbearing potential (IOCBP). ii) Is an IOCBP and using a contraceptive method that is highly effective (with a failure rate of < 1% per year) during the study intervention period and for at least 3 days after discontinuation of the study intervention and agrees not to donate eggs (ova, oocytes) for the purpose of reproduction for the same period. Exclusion Criteria - Participants must not weigh < 30.0 kg at Screening and Day 1. - Participants must not have non-plaque psoriasis (ie, guttate, inverse, pustular, erythrodermic, or drug-induced psoriasis) or any skin condition other than plaque psoriasis that could interfere with assessments of treatment effect at Screening or Day 1. - Participants must not have a history of serious bacterial, fungal, or viral infection requiring hospitalization and intravenous (IV) antimicrobial treatment within 60 days prior to Day 1. - Participants must not have any untreated bacterial infection within 60 days prior to Day 1. - Participants must not have any ongoing evidence of chronic bacterial infection (eg, chronic pyelonephritis, chronic osteomyelitis, chronic bronchiectasis). - Participants must not have herpes simplex/zoster, active tuberculosis (TB), hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus (HIV) infection-related exclusions. - Participants must not have received live vaccines or BCG within 60 days prior to Day 1 or plans to receive a live vaccine during the study, or within 60 days after completing study intervention. - Participants must not have had any prior exposure to deucravacitinib. - Participants must not have received any medication that is specifically prohibited. - Participants must not have a laboratory finding that is exclusionary. - Participants must not have any major illness/condition or evidence of an unstable clinical condition (eg, renal, hepatic, hematologic, gastrointestinal, endocrine, pulmonary, psychiatric, neurologic, immunologic, or local active infection/infectious illness) that, in the investigator's judgment or after consultation with the Sponsor's Medical Monitor, will substantially increase the risk to the participant if he or she participates in the study. - Participants must not have cancer or history of cancer (solid organ or hematologic including myelodysplastic syndrome) or lymphoproliferative disease within the previous 5 years. - Other protocol-defined Inclusion/Exclusion criteria apply.