HAVCR2 and familial pancreatic carcinoma: Approximately 40% to 70% of CD8A+ T lymphocytes co-expressed PDCD1 and/or HAVCR2 in both IF and TC, independently of the neoadjuvant chemotherapy (Figure 3A–C), suggesting that T cytotoxic lymphocytes are exhausted in the pancreatic cancer microenvironment.