T-cell engineering involves modifying T-cells to target specific antigens through two main methods: transferring genes encoding tumor-specific T-cell receptors or engineering T-cells with chimeric antigen receptors. Chimeric antigen receptors are artificial receptors that combine the antigen recognition domain of an antibody with T-cell activating signaling domains to redirect T-cell specificity. Engineered CAR T-cell therapies show promise in treating cancers by recognizing tumor-associated antigens and triggering T-cell mediated killing of cancer cells, though they still require pre-conditioning with chemotherapy.