Pancreatic ductal adenocarcinoma is an extremely lethal disease with the lowest 1-year and 5-year survival rates of any cancer. This is due, in part, to the extremely metastatic behavior of pancreas carcinoma cells and their extreme resistance to both chemical and radiotherapies. Importantly, we now know that a strong, but nevertheless unique, fibrotic and immunosuppressive stromal response is present in PDA. This intense fibroinflammatory, or desmoplastic, response is essentially pathognomonic for PDA and limits infiltration of anti-tumor immune cells and also their ability to move throughout and sample the tumor volume. Indeed, immunotherapies with immune checkpoint blockade or infusion of genetically modified cells are producing remarkable clinical responses in other advanced malignancies, but to date, success has been much more limited in PDA. However, focused preclinical strategies to disrupt the stroma or specifically engineer T cell therapies have shown promise in PDA. Thus, understanding the physical and molecular basis for native and engineered T cell infiltration and defining strategies to further enhance their infiltration, migration throughout tumor masses, and function in cancer will inform cell engineering strategies for improved treatment. Here, we test a number of focused hypotheses using advanced optical imaging with state-of-the-art in vivo systems, engineered environments, genome engineering, and mathematical modeling to better define how T cells successfully move through some environments but are impeded by others. We hypothesize that by defining design criteria that can be employed to help engineer T cells to move throughout tumor volumes we can profoundly improve therapeutic efficacy and employ combinations therapies to improve disease outcomes. Therefore, here, through advanced imaging and quantitative analysis we will dissect physical and molecular mechanisms governing migration and function of both native and engineered T cells. We will define the roles of both matrix architecture and immunosuppressive cells populations, and the links between the two. This information will provide tookits to engineer T cells that most effectively move throughout the entire tumor mass. Our goals are aligned with the TECH unit, where we will perform iterations between experiments, analysis, and technology development, and RTB-2 to define approaches to improve therapy in poor prognosis cancers. Collectively, we seek to elucidate fundamental mechanisms of immune cell migration and define approaches to transform cell engineering therapies to eradicate cancer.