KEYNOTE-028, a phase Ib study has reported an objective response rate (ORR) of 17.4% (95% CI: 5.0–38.8%) with pembrolizumab in a cohort of 23 heavily pretreated mCRPC patients with measurable disease and ≥1% PD-L1 expression in tumor or stromal cells. The gene discussed is CD274; the disease is neoplasm.