Project Summary/Abstract To end the HIV epidemic, we need integrated care models that address HIV and PrEP care, and co-existing substance use (SU) disorders that disrupt uptake and consistent use of effective interventions. The overarching goal of this R01 proposal is to conduct a randomized controlled trial to assess the ability of a Collaborative Care Prevention, Treatment, Navigation, Engagement, Resource (PrTNER) intervention to increase initiation of preexposure prophylaxis (PrEP) (for those at-risk for HIV) and decrease viral load (for those living with HIV) among young Black and Latino men who have sex with men (YBLMSM) through engagement in SU treatment. The Collaborative Care (CC) PrTNER is a multi-component intervention developed by members of our research team specifically for YBLMSM aged 15 to 24 who are at-risk for or living with HIV. This model moves beyond the individual to consider the broader context in which, substance use, and HIV risk are (re)produced. Enhanced models that integrate SU treatment into HIV and PrEP primary care services (using a collaborative care approach that incorporates feedback from a psychiatrist and support from a peer coach) are needed to address the nuance of substance use in this population. We, therefore, are proposing to conduct a randomized trial to evaluate an integrated collaborative care model (CC PrTNER) using the following aims: Specific Aim 1: To compare the proportion of YBLMSM with co-existing SU at risk for HIV infection who initiate (start or restart) PrEP over the 12 months in the CC PrTNER arm versus standard of care (SOC). Specific Aim 2: To compare the proportion of YBLMSM with co-existing SU living with HIV infection who are HIV virally suppressed at 12 months in the Collaborative Care PrTNER arm versus SOC. Specific Aim 3: To compare the effect of CC PrTNER versus SOC on non-tobacco SU in YLBMSM with co- existing SU and examine the effect of change in SU on PrEP uptake and HIV viral suppression. This proposal directly addresses goals 1, 2, and 4 of the 2022 National HIV/AIDS Strategy to End the HIV Epidemic through: prevention, treatment, and addressing co-existing SU disorders through comprehensive integrated care delivery. It further can transform the adolescent, health department and Ryan White care settings serving YBLMSM through harmonization of PrEP, HIV and SU treatment care delivery and implementation of a collaborative care model to address the multi-level barriers that impede uptake and adherence.