Uldrick TS, Gonçalves PH, Abdul-Hay M, et al. - Via a multicenter, open-label, nonrandomized, phase 1 study doner at seven Cancer Immunotherapy Trials Network sites, of 30 individuals with HIV, experts assessed the safety of pembrolizumab in people with HIV and advanced cancer and judged tumor responses. Most treatment-emergent adverse events at least probably associated with pembrolizumab were grade 1 or 2 (n = 22), and 20% (n = 6) were grade 3. The immune-related events of clinical interest comprised hypothyroidism (n = 6), pneumonitis (n = 3), rash (n = 2), an increased aminotransferase/alanine aminotransferase level (n = 1), and a musculoskeletal event (n = 1). One participant with pretreatment KS herpesvirus (KSHV) viremia acquired a polyclonal KSHV-associated B-cell lymphoproliferation and expired. HIV was constrained in all individuals. Gains in CD4 count were not statistically notable. Best tumor responses involved complete response (lung, n = 1), partial response (non-Hodgkin lymphoma (NHL), n = 2), stable disease for 24 weeks or more (KS, n = 2), stable disease for less than 24 weeks (n = 15), and progressive disease (n = 8) and two patients were not assessable. Thus, pembrolizumab has tolerable safety in patients with cancer, HIV treated with ART, and a CD4+ T-cell count of more than 100 cells/μL but may be correlated with KSHV-associated B-cell lymphoproliferation. The clinical advantage was seen in lung cancer, NHL, and KS. Moreover, anti-PD-1 therapy is relevant for the US Food and Drug Administration−approved indications and clinical trials in this population.