Immunotherapy of tumor: It is the application of immune enhancers or immunomodulators to enhance the immune function of the patient’s body or regulate the immune status of the patient in order to inhibit the development of tumor and facilitate the treatment and recovery of tumor. At present, many tumors have been proved to be caused by viral infections, therefore, the most fundamental prevention and treatment method is to use vaccines to prevent viral infections and thus prevent malignant tumors from occurring. At present, vaccines mainly include preventive vaccines and therapeutic vaccines. 1. Preventive vaccines prevent infection by inducing an effective humoral immune response, causing specific antibodies to bind to the envelope antigen of the virus, destroying the virus, and preventing the virus from entering the host cells. 2.Therapeutic vaccine belongs to specific active immunotherapy, and this vaccine has antiviral effect on viral gene transfer mice. From the development trend, the therapeutic virus vaccine will become a hot spot in the field of research on the treatment of viral infections, especially virus carriers in this century, and its combined application with existing antiviral drugs will become a new treatment method.