Budigalimab (ABBV-181), a monoclonal antibody that blocks the PD-1 immune checkpoint receptor on T cells, may help control HIV after stopping antiretroviral therapy (ART). Commonly used for cancer immunotherapy, checkpoint inhibitors restore T-cell activity. In a Phase I pilot study, 11 people on ART received four doses of 10 mg budigalimab every two weeks, while five received a placebo; they stopped antiretrovirals on the day of their first dose. Several budigalimab recipients showed delayed viral rebound or viral control. Six people considered good responders had a lower peak viral load after rebound than placebo recipients. One person maintained an undetectable viral load for about 50 days, then saw an increase to about 350 copies, followed by sustained suppression below 100 for 19 months. Another experienced a viral load spike about 20 days after ART interruption, followed by a rapid decline and sustained suppression below 200 for 18 months. These early findings suggest PD-1 inhibitors might be part of a combination functional cure strategy.