Anti-CEACAM1/CD66a Antibody is a humanized monoclonal antibody targeting carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1/CD66a). CEACAM1 is an immune checkpoint receptor widely expressed on immune cells (e.g., T cells, NK cells) and various tumor cells. Tumor cells evade immune surveillance by overexpressing CEACAM1 and engaging in homophilic interactions with CEACAM1 on immune cells to transmit inhibitory signals. This antibody specifically binds to CEACAM1, blocking these homophilic interactions, thereby relieving the suppression of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells and restoring their anti-tumor activity. It is widely used in immunotherapy research for melanoma, lung cancer, and gastrointestinal malignancies.