CHAMPION: Combining HIV And Meth Prevention and Treatment Interventions Optimized for HIV-Negative MSM

The goal of this randomized controlled trial is to pilot test new mobile health (mHealth) interventions to improve PrEP adherence among HIV-negative men who have sex with men (MSM) with mild to moderate methamphetamine use disorder (MUD). The CHAMPION intervention combines two mHealth tools-PrEPAPP and CBT4CBT-to address both HIV prevention and MUD treatment needs in this population. The study's specific aims are: * To evaluate the feasibility and acceptability of the CHAMPION intervention based on treatment retention and engagement rates. * To examine the preliminary efficacy the CHAMPION intervention to improve PrEP adherence, as measured by dried blood spot (DBS) tests compared to the waitlist control group.

Inclusion Criteria: 1. HIV-negative 2. Cis-gender male 3. Age 18-40 years old 4. Mild or moderate MUD (by DSM-5 SCID criteria) 5. Anal intercourse with one or more male partners in the past 6 months 6. Started daily oral PrEP more than 30 days ago and self-reported not always taking PrEP as prescribed in the past 30 days (consistent with PrEP It! inclusion criteria) 7. Willingness to participate in an mHealth study with a 6-month follow-up 8. Residing in San Diego or San Francisco County Exclusion Criteria: 1. Residing outside of San Diego or San Francisco County 2. Any condition that, in the principal investigator's judgment interferes with safe study participation or adherence to study procedures 3. Not able/willing to complete virtual/remote visits 4. Not willing to learn to self-collect dried blood spots using a finger stick