With the field evolving rapidly, with diverse new methodologies, this review seeks to offer a comprehensive overview of the various stain-to-stain approaches used in virtual staining for the BC immuno clinical biomarker panel: human epidermal growth factor receptor 2 (HER2), oestrogen and progesterone receptors (ER and PgR, respectively) and Ki67. Here, MKI67 is linked to breast cancer.