Key Figure, Figure 1. T cell differentiation trajectories impacting immunotherapy efficacy.

T cell function is limited by trafficking to the tumor as well as through immunosuppressive signals arising from the tumor microenvironment. Activation of the T cells requires antigen positive tumor cells as well as proper cross presentation and priming. Chronic antigen exposure results in epigenetic changes that include both DNA methylation and histone modifications consistent with T cell exhaustion.