ABSTRACT A key limitation to effective immunotherapy is the physical access of immune cells to the cancer cells. We propose to develop a multiscale tumor simulator to predict tumor dynamics based on immune and cancer cell migration and net proliferation as measured quantitatively from live cell microscopy. The tumor simulator will be developed by biomedical engineers working in close collaboration with immunologists and genetic engineers who are developing immunotherapies for pancreatic ductal adenocarcinoma and glioblastoma. The tumor simulator will be a computational platform that will help guide immunotherapy development and so will evolve to become an immunotherapy simulator. In addition, we will integrate state- of-the-art genome engineering and microenvironmental engineering to bring a full suite of engineering approaches to bear on the simulator development. Together, the simulator will be used to make quantitative, testable predictions that are then tested experimentally using pharmacological and genetic perturbations. By iterative model development we will test our central hypothesis that immune cell proximity is a major determinant of effective anti-tumoral immune response, and limiting to effective immunotherapy of solid tumors. Altogether, our Program Project will develop a comprehensive biophysics-based simulator to predict tumor progression and accelerate immunotherapy development.