Researchers are looking for new ways to treat HIV-1 (Human Immunodeficiency Virus Type 1). The usual (standard) treatment for HIV-1 is antiretroviral therapy (ART), which includes taking medicines to lower the amount of HIV-1 in the body. Standard ART helps people live longer, but people must take up to 3 medicines up to twice a day. Standard ART may also cause other health problems. Researchers want to know if a study ART works as well as a standard ART to treat HIV-1. The study ART combines 2 medicines, islatravir and ulonivirine, and is taken once a week. The goals of this study are to learn: 1) If the study ART works as well as a standard ART to treat HIV-1, and 2) About the safety of the study ART and if people tolerate it compared to a standard ART.