Up to now, PD-L1 expression was the only accepted biopsy-based biomarker, but with several weaknesses, such as tumor heterogeneity of PD-L1 expression, even within the tumor and between various tumor lesions of the same patient and false-negative results (Buttner et al., 2017; Bigras et al., 2018). This evidence concerns the gene CD274 and neoplasm.