Immunotherapy for early breast cancer: too soon, too superficial, or just right?

Immunotherapy emerged as a new treatment modality for breast cancer, and its use is approved in combination with chemotherapy for first-line therapy in metastatic triple-negative breast cancer overexpressing PD-L1. As immune checkpoint inhibitors alone have modest clinical activity in advanced breast cancer, there is a growing interest in combinatorial modalities, and particularly for their rapid development in the early disease setting. The plethora of ongoing immunotherapy trials in early breast cancer comes at a time when solid data in advanced disease are still imperfect. This review offers a perspective on the efforts to establish the efficacy and safety of immunotherapeutic agents in early breast cancer. •The investigation of immunotherapeutic agents for breast cancer has shifted from the metastatic to the early setting.•Different scenarios and designs exist for clinical trials testing immunotherapy in early breast cancer.•Combinatorial strategies may increase the activity of immunotherapy in early breast cancer across different subtypes.•Biomarkers for predicting upfront resistance, treatment response, and immune-related toxicities are needed.•Collaborative research is required for the understanding of the available data and the rational design of future trials.