found that several immune checkpoints and their ligand transcripts in tumor-infiltrating Treg cells were up-regulated in colorectal cancer or non-small cell lung cancer, and the specific signaling molecules were expressed on cell surface, such as interleukin-1 receptor 2 (IL1R2), programmed death (PD)-1Ligan1, PD-1ligand2, and CCR8 chemokines (63). Here, CCR8 is linked to neoplasm.