Triple-negative breast cancer (TNBC) is an aggressive biological subtype that accounts for 10–20% of invasive breast cancer and is associated with a worse prognosis. Advances in the understanding of tumor biology and the role of tumor-infiltrating lymphocytes (TILs) in breast cancer have paved way for clinical research evaluating immunotherapy in breast cancer, specifically TNBC. Efforts to delineate the role of immune checkpoint inhibitors in TNBC have culminated in several randomized controlled trials evaluating anti-PD-(L)1 antibodies in combination with chemotherapy, both in the metastatic and early breast cancer settings. As a result, therapy with immune checkpoint inhibitors has been integrated into the standard treatment regimens of stage II-III early TNBC, representing a crucial addition to the limited available treatments for this tumor subtype. In this chapter, we present a synthesis of the results of clinical trials that investigated the use of immunotherapy in breast cancer, particularly TNBC, with emphasis on efficacy and safety in the neoadjuvant and adjuvant settings.