Chimeric antigen receptor (CAR)-T cells are genetically engineered T cells from the patient that have shown remarkable efficacy as a treatment for hematological malignancies. However, CAR-T treatment for solid tumors has so far been unsuccessful. Solid tumors differ from hematological malignancies, as these present physical barriers against infiltration, contain a highly immune-suppressive environment, and harbor an unfavorable metabolic milieu. Therefore, new approaches are required to tackle these hurdles. The host lab was the first to identify an unconventional CD8 T cell (uT) population in humans, similar to the murine unconventional intraepithelial T cells. These cells are naturally tissue-homing and seem to perform an immune surveillance function. In this project, CAR-T cells will be generated using these uTs (CAR-uTs). To optimize this CAR-T cell product, the optimal costimulatory signal and growth factors to be provided to the cells will be determined using several in vitro and in vivo assays. Using single cell analysis on the immune infiltrate of patient derived xenografts (PDXs), the uT clones associated with tumor rejection will be characterized in depth. The information thus gathered, will be used to fully optimize CAR-uTs therapy, which will be tested in several PDX models of solid tumors.