Regarding the correlation between PD-L1 and CD8+ TILS, the evident association between the CD8+ TILS expression density and PD-L1 expression on tumor cells resulted from the mechanism of PD-L1/PD-1, which inhibited T cell activation by repressing transduction of the TCR signal and costimulation of CD28-CD80. This evidence concerns the gene CD28 and neoplasm.