Uldrick TS, et al. - In this open-label, nonrandomized, phase 1 multicenter study, researchers investigated whether it is safe to use anti-programmed cell death 1 therapy to treat people with both cancer and HIV with a range of CD4+ T-cell counts. They also assessed tumor responses. Eligible participants (n=30) had advanced cancer as well as HIV with a CD4 count greater than or equal to 100 cells/μL, antiretroviral therapy (ART) for 4 or more weeks, and an HIV viral load of less than 200 copies/mL. In three CD4 count-defined cohorts, pembrolizumab (200 mg) was given intravenously every 3 weeks for up to 35 doses. ART was continued. In individuals with HIV, a CD4 count of greater than 100 cells/μL, and advanced cancer, a satisfactory safety profile seen with pembrolizumab, but an unforeseen treatment-emergent adverse event of Kaposi sarcoma herpesvirus-related polyclonal B-cell lymphoproliferation occurred. Participants with Kaposi sarcoma, primary effusion lymphoma, diffuse large B-cell lymphoma, and lung cancer were clinically benefitted with pembrolizumab.