When analyzing prognosis in terms of BCSS, we found that high TILs significantly reduced the risk of breast cancer-related death by 55%, compared with low TILs (HR (95% CI) = 0.45 (0.22–0.93)) in the analysis including all patients, but not when limiting to the ER+/HER2− or any other individual IHC subtype (Table 3 and Table S3). This evidence concerns the gene ESR1 and breast cancer.