RecruitingBehavioural interventionCHAMPION: Combining HIV And Meth Prevention and Treatment Interventions Optimized for HIV-Negative MSMThe 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.