Advancements in Immune Checkpoint-Based Immunotherapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), characterized by the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, is a highly aggressive molecular subtype with high recurrence and metastasis rates. Due to the absence of reliable molecular targets, surgery combined with chemotherapy remains the mainstay of clinical treatment. In recent years, immunotherapy has provided new strategies for TNBC management. Immune checkpoints are key regulatory molecules that maintain immune homeostasis, and blocking these checkpoints can restore T cell activity and enhance tumor cell killing. Immune checkpoint inhibitors (ICIs) have demonstrated clinical benefit, particularly in combination with chemotherapy for patients with locally advanced or metastatic TNBC. This review focuses on immune checkpoint-based immunotherapy in TNBC, providing an overview from mechanistic insights to clinical applications and emerging therapeutic strategies. In addition to ICIs, we discuss alternative approaches, such as bispecific antibodies, antibody-drug conjugates (ADCs), chimeric antigen receptor T cell (CAR-T) therapy, tumor vaccines, and oncolytic viruses (OVs), highlighting their current research progress and clinical applications in TNBC treatment.