In a recent study on patients with different cancer types treated with anti-PD-L1 monoclonal antibody, MPDL3280A, the association of PD-L1 expression by infiltrating immune cells in pretreatment samples with objective response was stronger than that with tumor cell PD-L1 expression; therefore, these cells may be involved in a pre-existing T-cell activity suppression by PD-L1 before therapy. The gene discussed is CD274; the disease is cancer.