The study investigates the role of IL17-producing γδ T cells and neutrophils in promoting breast cancer metastasis. The authors found that tumors induce a systemic inflammatory cascade, which involves IL1β-activated γδ T cells producing IL17. This leads to the expansion and polarization of neutrophils, which then suppress cytotoxic CD8+ T lymphocytes, thereby facilitating metastasis. Neutralizing IL17 or G-CSF, or eliminating γδ T cells and neutrophils, significantly reduced pulmonary and lymph node metastases without affecting primary tumor growth. The findings suggest that targeting the γδ T cell-IL17-neutrophil axis could be a novel strategy to inhibit metastatic disease.The study investigates the role of IL17-producing γδ T cells and neutrophils in promoting breast cancer metastasis. The authors found that tumors induce a systemic inflammatory cascade, which involves IL1β-activated γδ T cells producing IL17. This leads to the expansion and polarization of neutrophils, which then suppress cytotoxic CD8+ T lymphocytes, thereby facilitating metastasis. Neutralizing IL17 or G-CSF, or eliminating γδ T cells and neutrophils, significantly reduced pulmonary and lymph node metastases without affecting primary tumor growth. The findings suggest that targeting the γδ T cell-IL17-neutrophil axis could be a novel strategy to inhibit metastatic disease.