Adoptive cell therapy (ACT) is an immunotherapy that uses engineered immune cells to combat cancer or infections, aiming for long-term disease control. Despite the success in Phase I clinical trial of the multi virus specific T cells by the Translational and Human Immunology Group at QIMR, patient responses have varied. This research seeks to explore the potential causes by identifying distinct T cell signatures in ACT products using single-cell RNA sequencing. By studying these signatures in a humanized murine model for their potential correlation with functionality and migratory kinetics, we aim to predict and enhance the therapeutic efficacy of ACT, leading to more targeted and effective immunotherapy.