Therefore, in order to investigate the role of ER stress‐related exosomes in prostate cancer cells promoting macrophage infiltration and polarization, laser scanning confocal microscope, RT-PCR, flow cytometric analysis, western‐blotting and cytokine bead array analyses were performed.The results demonstrated that TG-EXO downregulated the expression of PD-L1 on macrophages through flow cytometry analysis. This evidence concerns the gene CD274 and prostate cancer.