Given that CXCL12/CXCR4 interaction leads typically to the induction of the AKT pathway and afterward compromises MDSCs apoptosis, Jiang and coworkers suggested that plerixafor (AMD3100), a highly specific CXCR4 antagonist, could provoke a synergistic influence with anti-PD-1 antibody to enable tumor regression in a murine model of osteosarcoma [232]. Here, PDCD1 is linked to osteosarcoma.