PDCD1 and neoplasm: To test the hypothesis that an ICI could enhance the development of tumor antigen–specific immune responses, we performed a phase 1 study in which patients received the anti–PD-1 antibody nivolumab (3 mg/kg) in addition to our previously established combination of decitabine and NY-ESO-1 vaccination (ClinicalTrials.gov identifier: NCT 03358719; Figure 1A).