CD274 and non-small cell lung carcinoma: However, intra-tumoral heterogeneity and inter-tumoral heterogeneity of PD-L1 expression, the inter-observer variability in scoring PD-L1 staining, and reproducibility has reduced its accuracy as a biomarker to predict the response of NSCLC to anti-PD-L1 or anti-PD-1 therapies [29].