CD274 and non-small cell lung carcinoma: Although tumorous PD-L1 expression is a potential biomarker of the ICI therapeutic response, there is no widely accepted optimal biomarker to predict the efficacy of ICI, because ICI response and survival outcomes show heterogeneity in NSCLC patients receiving ICI therapy, regardless of PD-L1 expression level (Rittmeyer et al., 2017; Gandhi et al., 2018; Paz-Ares et al., 2018; Socinski et al., 2018).