SPDL1 and ovarian cancer: We could distinguish significantly positive correlations with the concentrations of sPD-L1 and the levels of expression of PD-L1 on both M-MDSCs (p = 0.03, Fig. 5g) and MO/MA (p = 0.02, Fig. 5h) in the blood but not in the ascites (p > 0.05, data not shown) of ovarian cancer patients.