CD274 and nonpapillary renal cell carcinoma: Co‐expression of PD‐1 and PD‐L1 was observed at a prevalence of 50% in a subset of ccRCC tumors with sarcomatoid differentiation.15 Thus, for PD‐1‐based assays, there may be variations in the same patient with regard to PD‐1 expression relative to the metastatic site being biopsied.