The lack of effective therapies for metastatic triple-negative breast cancer (mTNBC) highlights the need for the development of novel treatment strategies. The cornerstone of treatment has long been represented by chemotherapy. Relevant evidence has recently emerged regarding the efficacy of immune checkpoint inhibitors, with the demonstration of a statistically significant improvement of progression-free survival with the addition of atezolizumab to nab-paclitaxel in the first-line treatment of mTNBC, accompanied by a substantial overall survival benefit in the PD-L1-positive subgroup. Despite this, it is necessary to identify the biomarkers that could allow a better selection of patients and combination regimens.
