LAG3 is the third clinically targeted inhibitory receptor pathway, it can increase the expression of CD4 +, CD25- and promote T cell dysfunction in tumor microenvironment (37, 38), and is significantly expressed in immunohistochemistry of solid tumors including pancreatic cancer, gastric cancer, colorectal cancer, melanoma, urogenital tract cancer, etc (39). The gene discussed is CD4; the disease is familial pancreatic carcinoma.