In combination with the anti-CXCL5 mAb, 1400 W or anti-GM-CSF mAb, anti-PD-L1mAb reduced PMN-MDSC accumulation in the primary tumours, bone marrow and the lungs more significantly than anti-PD-L1 mAb treatment alone or anti-CXCL5 mAb, 1400 W or anti-GM-CSF mAb treatment alone (Fig. 6b, c). Here, CD274 is linked to neoplasm.