They found that anti-PD-1 mAb treatment induced the upregulation of TIGIT in CD8+ TILs in Trp53 KO/C-MycOE mice, which is a highly aggressive HCC model; however, the compensatory expression of TIGIT upon PD-1 blockade was not observed in Hepa1-6-bearing mice that are known to be an anti-PD-1-sensitive orthotopic HCC model. The gene discussed is PDCD1; the disease is hepatocellular carcinoma.