PDCD1 and hepatocellular carcinoma: Given the oncogenic potential of CXCL12/CXCR4 signaling, blockade of the CXCL12/CXCR4 axis might therefore synergize with current standard treatments—sorafenib and immune checkpoint inhibitors such as anti–PD-1—in the context of advanced HCC (9, 17), the concept of which has been experimentally validated by the discovery of a CXCR4 antagonist, BPRCX807.