Immunotherapies in breast cancer: harnessing the cancer immunity cycle

INTRODUCTION: Immunotherapies have found limited success in breast cancerdue to significant challenges within the tumor that block T-cell activity and function. AREAS COVERED: The current review discusses clinically relevant immunotherapeutics and trials within the framework of the cancer-immunity cycle. EXPERT OPINION: Current therapies such as antibody-drug conjugates and immune checkpoint blockade require proper biomarker selection, such as PD1 expression and the degree of tumor-infiltrating lymphocyte (TIL) infiltration to subset potential responders. HER2 and other tumor-associated antigens have served as valuable benchmarks for developing novel therapies, such as antibody engagers and CAR T-cells. However, further research is essential to identify and validate new target antigens that can enhance therapeutic efficacy and broaden the clinical applicability of these approaches.