PDCD1 and neoplasm: Ectopic expression of Tox in effector T cells induced a transcriptional program associated with TEX in vitro, and deletion of Tox could rescind the exhaustion program in tumor-specific CD8+ T cells, for example, Tox-deleted exhausted CD8+ T cells could not upregulate genes encoding for inhibitory receptors, including Entpd1, Pdcd1, Tigit, Havcr2 and Cd244 and reserved high expression level of TCF-1 (37).