CD274 and neoplasm: However, a higher level of PD-L1 expression in tumor-infiltrating immune cells especially tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) has been detected and proved to be associated with patients’ survival.7 49 Since these cells are important for tumor progression, efficacy of targeting PD-L1 on tumor-infiltrating immune cells should be further studied.