Some clinical trials of PD-L1 antibodies have reported response rates of only 30%–45%, even in patients with high tumor PD-L1 expression (≥50% TPS).37 38 Conversely, approximately 10% of patients with tumors lacking PD-L1 expression respond favorably to nivolumab.38 39 These unexpected responses suggest that tumor PD-L1 expression is highly heterogeneous, which renders PD-L1 IHC of biopsy samples an unreliable predictor of response. This evidence concerns the gene CD274 and neoplasm.