Here, we aimed to decipher the interaction between a neutrophil subset characterized by high expression of lymphocyte antigen 6 complex locus g (Ly6g<sup>high</sup>) and cluster of differentiation 8-positive T lymphocytes (CD8<sup>+</sup> T cells), mediated via cathelicidin embedded in NETs, as well as their synergistic mechanism and cooperative role in promoting lung metastasis of BC. This evidence concerns the gene CD8A and breast cancer.