This is a large final-stage (Phase 3) clinical trial testing whether people living with HIV, who already have their virus under control on the standard daily HIV pill (Biktarvy® – a combination of Bictegravir/Emtricitabine/Tenofovir alafenamide), can safely and effectively switch to a new treatment that is taken just once a week (Islatravir + Lenacapavir).