Enhanced cytotoxicity of engineered T cells by radiotherapy might be achieved through the following (49–52): 1) The DNA-damaging properties of ionizing radiation kill tumor cells and trigger pressure signals; 2) Sensitivity to apoptosis of radiation-treated cancer cells was enhanced; 3) A favorable tumor microenvironment is provided by upregulation of MHC class I, which enables CAR-T cells infiltration and increases IFNγ production. The gene discussed is IFNG; the disease is neoplasm.