F. nucleatum produces the trimeric autotransporter adhesin CbpF, which specifically binds to Carcinoembryonic Antigen-related Cell Adhesion Molecule 1(CEACAM1) on TILs and NK cells, thereby suppressing the antitumor activity of TILs and NK cells by activating the human inhibitory checkpoint receptor CEACAM1.And the non-lectin domain of Fibroblast Activation Protein Alpha inhibits the anti-tumor activity of tumor-infiltrating lymphocytes (TILs) and natural killer (NK) cells by activating the human inhibitory receptor T cell immune receptor with Ig and ITIM domains checkpoint (81). Here, CEACAM1 is linked to neoplasm.