After near-infrared light irradiation, the engineered EcN was able to produce and secrete flaB at tumor sites, successfully promoting TAMs polarization toward M1, activating immune responses, increasing the infiltration ratio of CD4+ as well as CD8+ T lymphocytes in the TME, and improving the immune-suppressive microenvironment of cold tumors, thus exerting anti-tumor effects. The gene discussed is CD4; the disease is neoplasm.