To evaluate whether the elevated PD-L1 expression in S/R RCC is driven by PD-L1 gene amplification, as previously reported6,17, we compared IHC-based PD-L1 expression by CD274 (or PD-L1) gene copy number status (N = 63 patients in the S/R CheckMate cohort). The gene discussed is CD274; the disease is renal cell carcinoma.