Inclusion Criteria:  18 years old or older; Both male & female; Psoriasis diagnosis (per dermatologist) for at least 2 years (in at least 30% of participants); Willing and able to provide informed consent; Fulfillment of HR-PsO criteria (Psoriasis (PsO) patients will meet the definition of HR if they fulfill the following criteria: a) PsO duration >2 years and Psoriasis Body Surface Area (BSA) >3% and positive imaging findings in MSKPDUS defined as a RM-PsASon score of >3.36  Exclusion Criteria:  Evidence of inflammatory joint pain, enthesitis and/or dactylitis on exam; Current systemic immunosuppressive medication use (i.e., methotrexate, apremilast) at the time of enrollment or biologic therapy (ever); RA seropositivity (mid-high RF/ACPA titers); Current active malignancy; History of symptomatic polyarticular OA or other joint conditions (such as RA, gout, etc) that may impair the ability to assess for PsA development Conditions where initiation of guselkumab is prohibited in the prescribing information, including clinically important active infection and untreated latent tuberculosis; Known hypersensitivity to the study agent.