The continuously secreted PD-1-TREM2 scFv could target the TME, block the PD-1/PD-L1 signaling pathway, as well as ligand binding to the TREM2 receptor present in MDSCs and TAMs, thereby reversing its immunosuppressive effects, and showed superior antitumor efficacy in colorectal cancer. Here, PDCD1 is linked to colorectal cancer.