CD274 and neoplasm: It has been clinically evaluated that the expression of PD-L1 on tumor tissue is useful as a predictive biomarker fin response to the PD-1 pathway blockade; however, the incidences of patients who respond to the PD-1/PD-L1 blockade without PD-L1 expression in their tumor tissue indicate the insufficiency of this predictive technique [10,11,12].