In recent years, with the change of people’s lifestyle and environmental factors, the incidence of tumor has been increasing year by year, and now it has become the “number one killer” leading to the death of residents. Tumor biotherapy is a brand-new tumor treatment method that emerged from the rapid development of tumor immunology and bioengineering technology. It mainly mobilizes the host’s natural defense mechanism or gives some substances to the body to obtain anti-tumor effect, i.e. to enhance the patient’s resistance by using some biological response modifiers, so as to achieve the purpose of killing and inhibiting tumors. With the application of a large number of biotherapeutic agents in clinical practice, biotherapy has become the fourth major therapy for tumors and is receiving increasing attention. Dendritic cell (DC) therapy combined with cytokine-induced killer cells (CIK) therapy is one of them, which has been widely used in clinical practice and has achieved good clinical results. DCs are the most effective specialized antigen-presenting cells in the human body, which can uptake, process, and deliver different types of antigens, activate initial T cells, and trigger antigen-specific immune responses. DC and CIK are two important parts of tumor immunotherapy, the former recognizes the pathogen and initiates the acquired immune system, while the latter kills tumors by exerting its own cytotoxicity and secretory cytokines, and is considered as a new hope for tumor over-the-top immunotherapy. DCs are the most powerful antigenpresenting cells (APCs), which can effectively stimulate the T-cell response. The immune response of the body is first captured by the original presenting cells, which process and process the antigen, and then present the antigen to T and B lymphocytes, thus triggering a series of immune responses. Dendritic cells, as the most powerful APC, stimulate the initial T cells (naive cells), stimulate the initial immune response, and play a powerful immune surveillance function in the body. However, the antigen processing and delivery of DC cells are restricted by MHC molecules, and only antigens restricted by MHC class I molecules are delivered to CD8+ T cells to induce the body to produce antigen-specific CTL in order to produce antitumor immune effects. DCs can enhance the cytotoxic and antitumor effects of CTL, and also enhance the cytotoxic effects of CIK. CIK is a non-specific cytotoxic effector cell induced by stimulation of peripheral blood mononuclear cells in vitro by cytokines such as IFN-γ, CD3 monoclonal antibody and IL-2. Among all the immune effector cells found today, CIK cells have strong proliferative capacity and strong cytotoxic activity, showing great promise in tumor immunotherapy. Other immune effector cells, such as lymphokine-activated killers (LAKs), are limited in clinical promotion because of their low in vitro proliferation capacity and low in vivo tumor cell killing activity. Tumorinfiltration lymphocyte (TIL) has MHC-restricted tumor cell killing activity, and although it is stronger than LAK cells, TIL cells are also difficult to be used in clinical treatment because of the possible alteration of the function of TIL cells isolated from tissues and the difficulty in obtaining the right number of cells. The killing activity of CIK cells is significantly higher than that of LAK cells, with non-MHC restriction and CIK cells, unlike TIL cells, need direct contact with tumor cells to proliferate, and the inhibition of normal bone marrow cells is slight, so they can be used for cellular peri-immunotherapy of malignant tumors and the decontamination of microscopic residual disease during autologous hematopoietic stem cell transplantation, and are the preferred option for next-generation peri-immunotherapy [9-221]. CIK cells are non-specific killer cells induced by various cytokines, capable of secreting various cytokines (e.g. IL-4, IFN -γ, etc.), and have stronger killing activity than LAK and CD3AK cells. The maximum proliferation of CIK cells from tumor patients in vitro can be more than 500 times, and their in vitro killing activity is significantly higher than that of LAK cells. In clinical studies, it was found that some tumor patients with less than optimal efficacy in the secondary immunotherapy with immune effector cells, which was thought to be due to the resistance of tumor cells to these immune effector cells, might be related to the lack of functional DCs in tumor patients. Therefore, combining CIK cells and DCs in the treatment of malignant tumors, using the non-MHC-restricted nature of CIK cells to compensate for the MHC-restricted nature of DCs, will help to relieve the immune incompetence of T cells in some tumor patients, thus playing a synergistic anti-tumor effect. This will lead to better anti-tumor effects and improve the long-term survival and quality of life of tumor patients.