Downregulation of the chemokine C-X-C motif chemokine (CXCL)12 and its ligand C-X-C chemokine receptor type 4 (CXCR4) affects NK cell trafficking in the BM, and weakens antitumor immune responses at the primary tumor site in patients (Tomaipitinca et al., 2021) (Figure 2). Here, CXCR4 is linked to neoplasm.