Tumor is one of the major diseases that seriously endanger human life, among which lung cancer, stomach cancer, liver cancer, esophageal cancer, colorectal cancer and breast cancer are the main types of cancers that occur and die. Due to the unlimited growth, infiltration and metastasis of malignant tumors, the conventional treatment methods of surgery, radiotherapy and chemotherapy nowadays cannot completely remove or kill tumor cells, therefore, tumor metastasis or recurrence often occurs; moreover, the specificity of conventional chemotherapy is low, which brings great damage to normal cells while killing tumor cells, especially damaging the immune system of the body, which plays an important role in the anti-tumor mechanism. There are more serious adverse effects, and cancer patients are often forced to stop receiving treatment because they cannot tolerate it. Because of its safety, effectiveness and low adverse effects, biologic therapy has become the fourth mode of tumor treatment after surgery, radiotherapy and chemotherapy. Tumor biotherapy is a new therapy that applies modern biotechnology and its related products for tumor prevention and treatment, and obtains anti-tumor effects by mobilizing the host’s natural defense mechanism or giving naturally produced highly targeted substances. The most commonly used biological therapies are immunotherapy, gene therapy, anti-neoangiogenic therapy, tumor lysing virus therapy, stem cell therapy, induction of differentiation and apoptosis, endocrine therapy, etc. Immunotherapy Immunotherapy includes cytokine therapy, immune cell therapy, monoclonal antibody and coupling therapy, and tumor vaccine therapy. Cytokine therapy Cytokines are small molecules of soluble peptides synthesized or secreted by activated immune cells (lymphocytes, monocytes, etc.) or mesenchymal cells (vascular endothelial cells, fibroblasts, etc.), which have the functions of controlling cell growth and development, participating in the body’s immune response, inflammatory response, and inhibiting or promoting tumor cell growth, IFN-β, IFN-γ), interleukins (IL-2, IL-4, IL-7, IL-12), hematopoietic stimulating factors (EPO, TPO, G-CSF, GM-CSF, IL-11, IL3), tumor necrosis factor (TNF-α), repair factors (GM1, EGF, BFGF), etc. Cytokines can induce the expansion and activation of autoimmune cells in cancer patients to resist tumor cells. Immunocell therapy Immunocell therapy is to isolate and obtain patients’ autoimmune cells, and under the induction of cytokines, expand a large number of immune effector cells with high anti-tumor activity, and then infuse them back into patients to directly kill tumor cells or correct the low cellular immune function of the body to achieve the purpose of tumor treatment. The purpose is to directly kill tumor cells or correct the low cellular immune function to treat tumor. These cells include cytokine-induced killer cells (CIK), lymphokine-activated killer cells (LAK), tumor-infiltrating lymphocytes (TIL), dendritic cells (DCs), CD3 antibody-activated killer cells (CD3AK), and bioengineered cytotoxic T cells. The use of such biologic therapies has been clinically used for a variety of tumors and cancerous thoracic ascites with mild adverse effects. Tumor vaccines Tumor vaccines are a class of biological effect modifiers, which are divided into preventive and therapeutic tumor vaccines. Tumor cells or their extracts are used to actively immunize cancer patients, specifically stimulate and enhance the body’s active immune rejection response to tumors, stop the growth, spread and recurrence of tumors, so as to achieve the purpose of tumor clearance or control, or directly lyse tumor cells and cause effective anti-tumor immune response by increasing the activation of immune cells. Monoclonal antibody and its couples therapy Monoclonal antibody immunotherapy has become a new hot spot in tumor treatment because of its high safety and efficacy. Therapeutic approaches of monoclonal antibodies include direct cytotoxicity mediated by monoclonal antibodies through complement, antibody-dependent cytotoxicity or induction of apoptosis; monoclonal antibodies coupled with drugs, toxins, radionuclides and anti-immune effector cell monoclonal antibodies; anti-unique antibodies to elicit unique immune responses; inhibition of growth factors and their receptors; in vivo tumor purification or activation of immune lymphocytes. Gene therapy for tumors is the use of genetic engineering techniques to treat tumors by directly correcting structural and/or functional defects in tumor cell genes, or indirectly by enhancing the host’s ability to kill tumors and the body’s defensive functions. Anti-neoangiogenic therapy The sustained growth and metastasis of tumors depend on the generation of new blood vessels, and when the size of tumors exceeds 1 to 2 mm, their growth is maintained by the generation of new blood vessels. Therefore, the biological treatment of tumors targeting neovascularization has become a hot research topic in recent years. Lymphotropic virus therapy Lymphotropic virus, also known as tumor-proliferating virus, has the ability to specifically infect and lyse cancer cells, selectively infect tumor cells and replicate in tumor cells in large numbers and eventually lyse tumor cells, releasing viruses that can infect more tumors; theoretically, it cannot replicate in normal cells and therefore has no killing effect on normal cells. The development of anti-cancer drugs will shift from the attack of cytotoxic drugs to the regulation of non-cytotoxic drugs in the century of tumor treatment, in which biological therapy will play an important role. Although biologic therapies are still in the preliminary stage of development, there are many clinical cases of successful treatment, which bring new hope to tumor patients. The urgent issues to be solved in biological therapy include: ( 1) discovering more meaningful molecular targets for tumors, continuously improving the killing power of tumors and breaking the immune tolerance state of the body. ( 2) To establish standardized treatment protocols to further improve the clinical efficacy of biologic therapy. ( 3) Reduce the cost of treatment. ( 4) Combine biological therapy with traditional radiotherapy and other means to exploit their synergistic effects to achieve better therapeutic effects, thus exploring new individualized treatment models. ( 5) There are large individual differences in the effect of biological therapy, therefore, it is important to find biomarkers that can effectively predict the effect of treatment for its promotion and application in clinical practice.