At present, the main treatment method of breast cancer is surgical excision, and radiotherapy and chemotherapy do not have obvious efficacy in the treatment of breast cancer. With the development of biotechnology, the role of DC-CIK cellular immunotherapy in the treatment of breast cancer has become more and more obvious. Since the 1980s, when successive cellular immunotherapy opened up a new field of biological treatment for breast cancer, after more than 20 years of research and practice by experts and medical practitioners at home and abroad; nowadays, biological cellular immunotherapy (DC-CIK) has become a new effective treatment for metastatic breast cancer. The current biological cellular immunotherapy (DC-CIK) has become a new and effective treatment for metastatic breast cancer. Appropriate immunotherapy can help remove the remaining cancer cells in the patient’s body and address the subclinical metastases that are difficult to resolve with conventional therapy, thus further improving and consolidating the efficacy of breast cancer, reducing recurrence and improving the quality of life of tumor patients. CIK cells are non-specific killer cells induced by various cytokines, which can secrete various cytokines (such as IL-4 , IFN-γ, etc.) and have stronger killing activity of LAK and CD3AK cells. The resistance of tumor cells to these immune effector cells may be related to the lack of functional DCs in tumor patients, which play an important role in the activation of cytotoxic T cells as powerful and specialized antigen-presenting cells in vivo. Co-culture of CIK cells and DCs significantly increased the specificity of antigen presentation by dendritic cells and co-stimulatory molecules, and in addition, co-culture of the two also promoted IL-12 secretion from dendritic cells and cytotoxicity of CIK cells, while IL-12 uptake blockade attenuated the cytotoxicity of CIK cells. Therefore, the combination of CIK cells with DC for the treatment of malignant tumors will help to relieve the immune incompetence of T cells in some tumor patients, thus exerting a synergistic anti-tumor effect. Indications for DC-CIK biological cell immunotherapy: ①Tumor patients who are insensitive to or have failed radiotherapy treatment; ②Tumors with strong tumor immunogenicity, such as small cell lung cancer, non-small cell lung cancer other than squamous carcinoma, certain types of breast cancer (immunohistochemistry), metastatic colorectal cancer, ovarian cancer, kidney cancer, prostate cancer, melanoma, etc.; ③Treatment to prevent metastasis and recurrence after tumor surgery.