CD274 and neoplasm: Previous research has shown that PD-L1 expression is involved in two main mechanisms: the innate immune escape, which is associated with multiple oncogenes, and the adaptive immune escape, which consists of various tumor microenvironment inflammatory factors (Zhang et al., 2013; Pardoll, 2012; Rech & Vonderheide, 2013; Taube et al., 2012).