Cancer immunotherapies, first and foremost checkpoint blockade therapy (CBT), have revolutionized the treatment landscape of cancer patients, however to date long-term clinical benefit is restricted to a minority of cancer patient. Responses to immunotherapy have been correlated to the presence of cytotoxic T cells within the tumor microenvironment and to the fact that these tumor-reactive cytotoxic T cells have lost the functional ability to eliminate tumor cells. This terminal state of T cell differentiation is often referred to as T cell exhaustion and CBT agents can reinvigorate such exhausted T cell responses. However, not all anti-tumor T cell responses follow this path of differentiation. Some remain functional and can successfully eliminate the cancer while others never gain full effector potential and are refractory to CBT. We have generated a set of mouse models, allowing us to study T cell and dendritic cell interactions in the tumor as well as the tumor-draining lymph node to understand the molecular determiniats for all favors of anti-tumor T cell responses.