The purpose of this Notice of Funding Opportunity (NOFO) is to support pilot research to develop and test behavioral implementation strategies for biomedical interventions (e.g., oral PrEP, condoms) to improve HIV and STI prevention implementation among disproportionately affected populations, especially Black/African American (Black) and Hispanic/Latino (Hispanic) gay, bisexual, and other men who have sex with men (MSM) without HIV who report substance use (drug or alcohol). The study design and sample size should meet minimum r...