PDCD1 and neoplasm: It has been established that TAMs decrease the cytotoxicity of T cells and NK cells because they express PD-L1, which are ligands for the programmed cell death 1 (PD-1) and CTLA-4 receptors.292,293 TAM-derived chemokines and cytokines may interact with bone MDSCs, tumor-related DCs, and neutrophils to create an inhibitory TME.294 TAM-produced IL-10 and TNF-α further decrease antitumor T cell function by inducing the expression of PD-L1.