CD274 and neoplasm: In terms of TAMs, their polarization toward M1 or M2 subsets in the tumor microenvironment has attracted a lot of attention and ample evidence exists that TAMs appear and behave as M2 phenotype, which is an important factor in protumorigenesis.50 It is, therefore, necessary to include TAMs and MDSCs to have a better understanding of the roles of PD-1/PD-L1 in different cells and of the function of TAMs polarization in the tumor microenvironment.