Engineered T cells, or "living drugs," represent a groundbreaking advancement in cancer immunotherapy. These cells are genetically modified to enhance their ability to target and destroy cancer cells, particularly in hematologic malignancies. The development of chimeric antigen receptors (CARs) and T cell receptors (TCRs) has significantly improved the specificity and efficacy of T cell therapy. CARs, which combine elements of B cell receptors and T cell receptors, allow for MHC-independent targeting of tumor antigens, making them highly effective against B cell malignancies such as B-cell acute lymphoblastic leukemia (B-ALL). CD19 is the most commonly targeted antigen in these therapies, with CD19-targeted CAR T cells showing remarkable clinical responses in patients with relapsed/refractory B-ALL. Similarly, NY-ESO-1-specific TCR-engineered T cells have demonstrated efficacy in multiple myeloma and synovial cell sarcoma. Beyond B-cell malignancies, engineered T cells are being explored for non-B-cell hematologic malignancies, including plasma cell myeloma. Targets such as BCMA and CD33 are under investigation for their potential in treating these conditions. Additionally, solid tumors are being targeted using engineered T cells, with potential targets including GD2, IL13Ra2, and mesothelin. These therapies have shown promise in preclinical models and early clinical trials, although challenges remain in terms of specificity, off-tumor effects, and long-term safety. The field of engineered T cell therapy is rapidly evolving, with ongoing research into novel targets, improved gene editing techniques, and strategies to enhance trafficking and avoid tumor suppression. Innovations such as Boolean logic gates, which allow for controlled activation and deactivation of T cells, are being explored to improve safety and efficacy. Furthermore, the development of allogeneic T cell therapies and the use of gene editing to enhance T cell function are key areas of focus. Despite these advancements, challenges such as tumor immunosuppression, off-tumor toxicity, and the need for long-term safety monitoring remain significant hurdles. The future of cancer immunotherapy is likely to be shaped by continued advancements in engineered T cell technology, offering new hope for patients with previously untreatable cancers.Engineered T cells, or "living drugs," represent a groundbreaking advancement in cancer immunotherapy. These cells are genetically modified to enhance their ability to target and destroy cancer cells, particularly in hematologic malignancies. The development of chimeric antigen receptors (CARs) and T cell receptors (TCRs) has significantly improved the specificity and efficacy of T cell therapy. CARs, which combine elements of B cell receptors and T cell receptors, allow for MHC-independent targeting of tumor antigens, making them highly effective against B cell malignancies such as B-cell acute lymphoblastic leukemia (B-ALL). CD19 is the most commonly targeted antigen in these therapies, with CD19-targeted CAR T cells showing remarkable clinical responses in patients with relapsed/refractory B-ALL. Similarly, NY-ESO-1-specific TCR-engineered T cells have demonstrated efficacy in multiple myeloma and synovial cell sarcoma. Beyond B-cell malignancies, engineered T cells are being explored for non-B-cell hematologic malignancies, including plasma cell myeloma. Targets such as BCMA and CD33 are under investigation for their potential in treating these conditions. Additionally, solid tumors are being targeted using engineered T cells, with potential targets including GD2, IL13Ra2, and mesothelin. These therapies have shown promise in preclinical models and early clinical trials, although challenges remain in terms of specificity, off-tumor effects, and long-term safety. The field of engineered T cell therapy is rapidly evolving, with ongoing research into novel targets, improved gene editing techniques, and strategies to enhance trafficking and avoid tumor suppression. Innovations such as Boolean logic gates, which allow for controlled activation and deactivation of T cells, are being explored to improve safety and efficacy. Furthermore, the development of allogeneic T cell therapies and the use of gene editing to enhance T cell function are key areas of focus. Despite these advancements, challenges such as tumor immunosuppression, off-tumor toxicity, and the need for long-term safety monitoring remain significant hurdles. The future of cancer immunotherapy is likely to be shaped by continued advancements in engineered T cell technology, offering new hope for patients with previously untreatable cancers.