In turn, a correlation between IL-6 overexpression and decreased number of CD8+ and CD4+ lymphocytes but increased myeloid-derived suppressor cells (MDSCs) and regulatory/suppressor T cells in the CRC tumor was also reported, with a similar connection established between the overexpression of programmed death-ligand 1 (PD-L1) (a potent inhibitory regulator of antitumor immunity) and IL-6 in CRC. Here, CD4 is linked to colorectal carcinoma.