CAR-based immunotherapy for breast cancer: peculiarities, ongoing investigations, and future strategies Breast cancer is the most common malignancy in women, with significant global incidence and mortality. Current treatments for Luminal A, Luminal B, and HER2-positive breast cancers include surgery, chemotherapy, and endocrine therapy, but triple-negative breast cancer (TNBC) remains challenging due to limited treatment options. CAR-T cell therapy, initially successful in hematological malignancies, is now being explored for solid tumors, including breast cancer. Choosing suitable targets is crucial for effective CAR-T therapy in breast cancer. This review summarizes the effective and potential targets of CAR-T therapy in different breast cancer subtypes, particularly TNBC. CAR-based immunotherapy has shown promise in treating breast cancer, with CAR-macrophages, CAR-NK cells, and CAR-mesenchymal stem cells (MSCs) showing potential for solid tumors. However, the tumor microenvironment (TME) and side effects of CAR-T therapy pose challenges. CAR-T cells and CAR-NK cells-derived exosomes are advantageous in tumor therapy, with exosomes carrying CAR showing high expression of cytotoxic molecules and potential for safe treatment. This review discusses the development and challenges of CAR-based immunotherapy in breast cancer, focusing on CAR-expressing exosomes and their potential in treatment. It also elaborates on the development of CAR-T cells in TNBC therapy and the prospects of using CAR-macrophages, CAR-NK cells, and CAR-MSCs for breast cancer treatment. The review highlights the importance of targeting specific antigens, the role of the TME in CAR-T therapy, and the potential of CAR exosomes in breast cancer treatment. Despite progress, challenges such as toxicity, off-target effects, and CAR-T cell exhaustion remain. The review also discusses the potential of CAR-NK cells, CAR-M, and CAR-MSCs in breast cancer treatment, emphasizing their advantages over traditional CAR-T cells. The review concludes that CAR-based immunotherapy holds promise for breast cancer treatment, with ongoing research aiming to improve efficacy and reduce side effects.CAR-based immunotherapy for breast cancer: peculiarities, ongoing investigations, and future strategies Breast cancer is the most common malignancy in women, with significant global incidence and mortality. Current treatments for Luminal A, Luminal B, and HER2-positive breast cancers include surgery, chemotherapy, and endocrine therapy, but triple-negative breast cancer (TNBC) remains challenging due to limited treatment options. CAR-T cell therapy, initially successful in hematological malignancies, is now being explored for solid tumors, including breast cancer. Choosing suitable targets is crucial for effective CAR-T therapy in breast cancer. This review summarizes the effective and potential targets of CAR-T therapy in different breast cancer subtypes, particularly TNBC. CAR-based immunotherapy has shown promise in treating breast cancer, with CAR-macrophages, CAR-NK cells, and CAR-mesenchymal stem cells (MSCs) showing potential for solid tumors. However, the tumor microenvironment (TME) and side effects of CAR-T therapy pose challenges. CAR-T cells and CAR-NK cells-derived exosomes are advantageous in tumor therapy, with exosomes carrying CAR showing high expression of cytotoxic molecules and potential for safe treatment. This review discusses the development and challenges of CAR-based immunotherapy in breast cancer, focusing on CAR-expressing exosomes and their potential in treatment. It also elaborates on the development of CAR-T cells in TNBC therapy and the prospects of using CAR-macrophages, CAR-NK cells, and CAR-MSCs for breast cancer treatment. The review highlights the importance of targeting specific antigens, the role of the TME in CAR-T therapy, and the potential of CAR exosomes in breast cancer treatment. Despite progress, challenges such as toxicity, off-target effects, and CAR-T cell exhaustion remain. The review also discusses the potential of CAR-NK cells, CAR-M, and CAR-MSCs in breast cancer treatment, emphasizing their advantages over traditional CAR-T cells. The review concludes that CAR-based immunotherapy holds promise for breast cancer treatment, with ongoing research aiming to improve efficacy and reduce side effects.