Although one study showed that tumour cell PD-L1 was predictive of response across multiple cancer types while PD-L1 expression on TIIs did not reach statistical significance [17], other studies have shown that TII PD-L1 expression is more predictive of response than tumour PD-L1 expression [59–62], demonstrating the need for more research into TII PD-L1 expression. The gene discussed is CD274; the disease is cancer.