Our mouse scRNAseq dataset as well as bioinformatic analyses comparing patients with ER+HER2− breast cancer from the public METABRIC dataset11 based on transcriptional signatures of IL17 signaling pointed to CCL2 and its cognate receptor C-C motif chemokine receptor 2 (CCR2) as to potential drivers of γδ T cell infiltration in M/D-driven tumors responding to P+T. Here, CCL2 is linked to breast cancer.