Some tumor cells express high levels of PD-L1 to evade from immune system, as PD-1/PD-L1 interaction induces cytotoxic T cell inactivation and downregulation of immune responses (Schreiber et al., 2011), and PD-L1 expression was proposed to be a potential biomarker of response to pembrolizumab (Ghidini et al., 2021). This evidence concerns the gene CD274 and neoplasm.