CCR8 and non-small cell lung carcinoma: Marco et al. found that tumor-infiltrating Treg cells are upregulated in several immune checkpoints and express specific signaling molecules on the cell surface [51], such as interleukin-1 receptor 2 (IL1R2), programmed death (PD)-1 LIGAND1, PD-1 LIGAND2, and CCR8 (C-C Motif Chemokine Receptor 8) chemokines, which contributed to the immunosuppressive tumor microenvironment in non-small cell lung cancer (NSCLC) and colorectal cancer.