The tremendous potential of cancer immunotherapy is currently hampered by low response rates in patients due to so-called cold tumors that show low infiltration of innate immune cells as well as by immune-related toxicity as side effects. Therefore, there is an urgent need for more safe immunotherapies that allow for a more target-specific engineering of the immune system. To tackle these issues, the overarching goal of this project is to investigate novel supramolecular nanomaterials that engineer the tumor microenvironment (TME) to become an immunological hotbed. More specifically, we will focus on strongly improving the activity of anti-tumoral T cells in the TME. Hereto we will backpack immunotherapy-loaded nanomaterials onto tumor-homing T cells to deliver agonists of Stimulator of Interferon Genes (STING). These innovative drug molecules provoke potent innate immune activation and thereby drive adaptive T cell mediated anti-tumoral immune responses that can kill cancer cells and suppress metastatic growth.