CXCR4 and neoplasm: Although the CXCL12/CXCR4 axis is directly or indirectly tumor-promoting and immunosuppressive, we have recently uncovered a counterbalancing activity: the promotion of cell phagocytosis by macrophages via a lateral interaction with CD47 on the cell to be ingested, that ultimately promotes the emergence of anti-tumor effector T cell clones [75].