ESR1 and breast cancer: While the evidence for the prognostic or predictive value of TILs or CD8+ T-cell density in luminal-like BC is limited and controversial [33, 44, 56, 65–68], our findings align with the study by Krijgsman et al. [44], who observed a positive trend between CD8+ density in tumor region and clinical outcomes in a cohort of 236 patients with ER+ invasive BC using machine learning-based approach.