Genetically engineered T-cell therapy holds great potential for the curative treatment across a series of cancers. However, drug-related safety concerns need to be addressed in the emerging medicine of the future. T cells are engineered through conventional methods like lentivirus, retrovirus or transposon, which randomly integrate exogenous gene cassette into T cell genome, accompanied by the risks of transcriptional silencing, oncogenesis, and variegated transgene expression. The development of robust gene-editing tools makes it possible to efficiently insert designed DNA fragments into specific locus of T cell genome, which lowers the risks caused by random integration. The authors review existing gene-editing tools for T cell engineering, and further discuss the next generation of CAR-T platforms for efficient delivery of gene-editing cargo into the target cells.