For instance, CAFs in pancreatic cancer have been reported to upregulate the expression of certain immune checkpoint molecules, including PD-1, cytotoxic lymphocyte-associated antigen-4 (CTLA-4), T cell immunoglobulin, mucin-domain containing-3 (TIM-3) and lymphocyte-activation gene-3 (LAG-3), on both CD4 + and CD8 + T cell surfaces, which consequently inhibits proliferating T cells and their specific recognition of tumor cells [261]. Here, CD4 is linked to neoplasm.