CXCR4 and neoplasm: In our quest to understand whether these two receptors (namely CXCR2 and CXCR4) differently impact neutrophils’ migration into the tumor, we noted that, in both 4T1 and AB12 models, NDN and LDN presented a high and very similar surface expression of CXCR2 and CXCR4, while TANs expressed significantly lower levels of these receptors, suggesting their possible involvement in the chemoattraction of circulating neutrophils into the tumor (Figure 2A,B, and Figure S2).