A previous study of primary breast cancer grouped 175 immune cells into three clusters: T cells, B cells, and M2 macrophages, all exhibiting an immunosuppressive phenotype.146 In contrast, Azizi et al. profiled 47,016 CD45+ cells from treatment-naïve patients with breast cancer and revealed significant heterogeneity for both lymphoid and myeloid cells.147 Moreover, the observed continuum of T cell states indicated that canonical classification of T cell clusters oversimplifies the tumor environment of breast cancer. Here, PTPRC is linked to breast cancer.