TIGIT and neoplasm: Simultaneous inhibition of the TIGIT/PVR and PD-L1/PD-1 pathways improved anti-tumor activity compared with blockade of only one pathway in mouse tumor models [5], and increased in vitro proliferation, cytokine production, and anti-tumor function of CD8 + TILs from patients with hepatocellular carcinoma or melanoma [7, 8].