CD274 and cancer: Considering the fact that the interaction of PD-L1 on tumor cells with PD-1 on TILs leads to escape of cancer cells from the immune system, it is not surprising, that upregulation of PD-1 by recombinant cytokines, stimulatory antibodies or transfer of activated adoptive T-cells increases the effect of PD-1/PD-L1 pathway blockage [27, 46, 47].