T-BsAb upregulates PD-1 on T cells and PD-L1 on tumor cells, and a combination of anti-CEA (carcinoembryonic antigen) BsAb and PD-L1 inhibitor improved anti-tumor efficacy by increasing the frequency of TILs when compared with each monotherapy in preclinical models [146]. Here, CEACAM5 is linked to neoplasm.