In still other studies, Yu et al. [33] reported that MDSC levels were increased in response to cytokine-induced killer cell therapy, a therapy performed by administering a mixture of immune cells to eliminate cancer cells, while Ou et al. [34] reported that PD-L1 can be expressed in an orthotopic model to clarify the role of PD-L1 in various immunotherapies. The gene discussed is CD274; the disease is cancer.