This article documents key moments in research and WHO policies that have informed how ART is applied within HIV programs, including as a prevention tool with the potential to support efforts to address HIV-related discrimination. In 2023, WHO continues to clarify that there is zero risk of sexual HIV transmission when a person living with HIV has an undetectable viral load and an almost zero or negligible risk of sexual transmission when a person living with HIV has a viral load of ≤1000 copies/mL.