Using murine models of spontaneously metastatic breast cancers, Liu et al. found that neoadjuvant anti-PD-1 therapy resulted in a significant increase in tumor-specific CD8+ T cells, and they noted that tumor-specific CD8+ T cells from neoadjuvantly treated models with regulatory T cell depletion displayed an effector/memory phenotype26. Here, PDCD1 is linked to breast carcinoma.