Previously, we have mapped the tumor antigen landscape of the CT26 model where the novel tumor epitope GSW11 has been shown to be abundantly expressed in CT26 tumors and contributed to the immunodominant response among tumor-infiltrating CD8+ T cells.21 However, despite the presence of T cell infiltration in tumors, CT26 is not immunogenic and is only moderately responsive to anti-PD-1. The gene discussed is PDCD1; the disease is neoplasm.