MKI67 and breast cancer: For this reason, here we set out to robustly compare between various methods of visual Ki67 assessment while considering practicality, time effectiveness, reproducibility, the prognostic and predictive value, heterogeneity, and the biological value of different staining intensities, patterns and sublocalisations utilising a large cohort of luminal ER‐positive and human epidermal growth factor receptor (HER2)‐negative BC to identify the optimal scoring method that can be clinically valid and applicable.