CD96 staining was also detected in tumor‐infiltrating CD8+ T cells but was only minimally detected in CD31+ endothelial cells or α‐SMA+ fibroblasts in patients with BC (Figure S1A, Supporting Information), which is consistent with the results of previous studies.[17] Importantly, the application of optimal cutoff points, as determined using X‐tile statistical software, revealed that 38.3% of patients with BC expressed high levels of CD96 (Figure 1B,C), and that such high tumoral CD96 expression was associated with worse disease‐free survival (DFS) and overall survival (OS) (Figure 1D). This evidence concerns the gene PECAM1 and breast cancer.