(80) found that myeloid-derived suppressor cells (MDSCs) with the CD45+CD33lowCD11bdim phenotype depleted L-arginine in the microenvironment through the IL-6/IL-8-arginase I axis and inhibited tumor cell killing by CD8+ T cells, and it is noteworthy that this type of MDSCs exhibits concomitant high expression of CD66b. The gene discussed is CD8A; the disease is neoplasm.