Tumors are a serious threat to human health. The current traditional methods of cancer treatment include surgery, chemotherapy, radiotherapy and targeted drug therapy. In recent years, tumor immunotherapy, especially chimeric antigen receptor (CAR) T cell immunotherapy has flourished in basic research and clinical application, and has achieved great success in the treatment of hematological malignancies. However, numerous studies have shown that various degrees of toxic and side effects may occur after cellular immunotherapy, and some patients relapse after remission. Therefore, it is of great significance to understand the challenges and limitations of cell therapy and find solutions to continue to exert the potential of cell immunotherapy. This article reviews the CAR structure, the selection of viral vectors, the challenges and prospects of cell therapy.