A Study to Learn About The Study Medicine (PF-07038124) In Patients With Mild To Moderate Atopic Dermatitis Or Mild To Severe Plaque Psoriasis.

The purpose of this clinical trial is to learn about the safety, how well the study medicine works, extent to which side effects can be tolerated, and how the study medicine is changed and eliminated from your body after you apply it on your skin. The study medicine is in ointment form. This study is seeking participants who If they have Atopic Dermatitis (AD): * Have a diagnosis for at least 3 months * Have a diagnosis of mild or moderate disease assessed using Investigator's Global Assessment (IGA) * Have percent Body Surface Area (%BSA) covering 5% up to 40% * A Peak Pruritus Numerical Rating Scale (PP-NRS) average score of ≥2 during the screening period If they have plaque psoriasis (PsO): * Have a diagnosis for at least 6 months * Have a diagnosis of mild, moderate, or severe disease assessed using Physician's Global Assessment (PGA) * Have percent Body Surface Area (%BSA) covering 2% up to 20% All participants in this study will receive either 0.01% PF-07038124, 0.03% PF-07038124, or a vehicle ointment. In addition, some participants with PsO will receive 0.06% PF- PF-07038124. Participants will not know which dose level they have received. The participants will be randomly assigned to each dose group. PF-07038124 ointment will be applied topically to affected areas once daily. We will compare the experiences of people receiving the different dose levels of the ointment to those who receive the vehicle ointment. This will help us determine if PF-07038124 ointment is safe and effective. Participants will take part in this study for approximately 21 weeks. Participants will apply the study medicine once daily for 12 weeks followed by a safety follow-up period of 4-5 weeks from last application of study medicine to last visit.