A preclinical study has shown that anti-PD-L1 agents only inhibit PD-L1/PD-1 and PD-L1/B7-1 signaling and restore tumor-specific T-cell immunity [18], whereas anti-PD-1 agents block both PD-L1 and PD-L2 binding to PD-1 [19]. Here, PDCD1 is linked to neoplasm.