(A) Kaplan-Meier analysis of abundance of CD3 T cells versus overall survival (OS) in TNBC discovery (left) and validation cohort (right). (B) Kaplan-Meier analysis of abundance of CD20 B cells versus OS in TNBC discovery (left) and validation cohort (right). (C) Multivariable CPH modeling adding patient age, tumor size, and stage to CD3 T cell high variable defined in A. (D) Multivariable CPH modeling adding patient age, tumor size and stage to CD20 B cell high variable defined in B. (E) Kaplan-Meier analysis of abundance of CD3 T cell versus OS in all patients who are ER⁺ (left) and patients who are ER⁺ with high (above the median) tumor proliferation (right). (F) CPH modeling of CD3 T cell abundance plus clinical variables in high- and low-proliferation ER⁺ tumors. (G) Kaplan-Meier analysis of all patients who are ER⁺ and patients with TNBC stratified into 4 groups by median tumor proliferation and median T cell abundance. (H) CPH modeling of CD3 T cell abundance plus clinical variables in high- and low-proliferation TNBC tumors. (I) Mean number of T cell neighbors (within 25 μm) of T cells in tissues from high- and low-proliferation ER⁺ or TNBC tumors in IMC cohort. (J) Ki67 intensity indicating proliferation levels of T cells in tissues from high- and low-proliferation ER⁺ or TNBC tumors in IMC cohort. (K) CD44 intensity in T cells, indicating memory/effector phenotypes in IMC tissues. (A–H) All Kaplan-Meier P values obtained from the log-rank test, validation cohort corrected for testing multiple cell types with Benjamini-Hochberg method. CPH modeling P values for cell type variable given in panel titles; the HR estimates are marked by boxes, and data are shown as 95% CI. (I–K) Significance was found with the Kruskal-Wallis test. Post hoc Tukey’s HSD was used for pairwise comparisons between groups. Box plots show the median and interquartile range (IQR), and whiskers indicate 1.5× the IQR.