I’m submitting S2S application via GMAS and there’s a subaward on it. I need to mark the subrecipient PI as Key personnel in GMAS so they appear on the Senior/Key personnel form in the application. Do I also need to mark the sub PI as an investigator?

When you add an individual to the research team and answer the question “Is this person responsible for the design, conduct or reporting?”, answer “No” for subcontractor investigators.  While they technically meet the definition, HMS has contracted with the subawardee institution to conduct the COI process for their investigators.