CD8A and cancer: Although great progress has been made in cancer immunotherapies, only a small part of patients respond to this treatment.[1, 2, 3, 4] A major challenge to eradicate cancer is the development of immune evasion, primarily in dysfunction of T cells that are critical in antitumor immunity.[5, 6, 7, 8, 9, 10, 11] In cancer patients, T cells, especially CD8+ T cells, are frequently incapable of eliciting antitumor responses, namely “anergy,”[12, 13, 14, 15, 16] but the cause and mechanism largely remains unknown.