This Antiretroviral Therapy as Long Acting Suppression every 2 Months (ATLAS-2M) study is designed to demonstrate the non-inferior antiviral activity and safety of CAB LA + RPV LA administered every 8 weeks (Q8W) compared to CAB LA + RPV LA administered every 4 weeks (Q4W) over a 48-week treatment period in approximately 1020 adult HIV-1 infected subjects. Subjects will be divided in 2 groups; Group 1 will include subjects receiving current anti-retroviral (ART) standard of care (SOC) therapy whereas group 2 will include subjects currently receiving CAB LA + RPV LA Q4W in ATLAS study. Subjects in both groups will be randomized to receive CAB LA + RPV LA Q4W or Q8W. The study will be carried out in 3 phases including screening phase, maintenance phase and extension phase. Subjects choosing not to enter the Extension phase can complete their study participation at the Week 100 visit and enter into the 52-week Long-Term Follow-Up (LTFU) Phase as required. A sub-study in the ATLAS-2M study will evaluate the pharmacokinetics, tolerability and efficacy of CAB and RPV long acting injections following intramuscular administration in the Vastus Lateralis Muscle (thigh) in HIV-infected Adult Participants who have received at least three years of Gluteal Injections in this ATLAS-2M Study.