RecruitingPhase 4Behavioural interventionOptimizing Evidence-based HIV Prevention Targeting People Who Inject Drugs on PrEPThe investigators will conduct an optimization trial among N=256 PWID newly started on medication for opioid use disorder and Pre-Exposure Prophylaxis (PrEP) to assess the performance of four intervention components (Attention, Executive Functioning, Memory, and Information Processing) aimed at enhancing the ability of PWID on MOUD to process and utilize HIV prevention content, leading to improvements in HIV prevention information, motivation, behavioral skills, and behaviors (IMB).