This study showed a decrease in the number of mouse brain-infiltrating Treg cells and an increase in the ratio of CD+8/Treg in the combination therapy group, further indicating that a combination of radiotherapy with anti-CEACAM1 treatment can reverse the immunosuppressive microenvironment in glioma tissues, inhibit tumour proliferation, and restore immune responses Fig. 7. Here, CEACAM1 is linked to neoplasm.