a. Anti-CEA CAR-T cells were successfully constructed and demonstrated the ability to autocrine the PD-1-TREM2 single chain variable fragment scFv antibody.b. Utilizing genetic engineering technology, the PD-1-TREM2 scFv antibody was integrated into CAR-T cells to enable them to target and specifically accumulate within the tumor microenvironment.c. In a mouse model of colorectal cancer, these modified CAR-T cells were administered intravenously to evaluate their antitumor effects. Here, PDCD1 is linked to colorectal cancer.