However, Wu et al. demonstrated in an NSCLC study that tumours with a high infiltrating PD-L1+ lymphocyte level in the stroma were more frequently detected with high CD8+ T effector cells, demonstrating positive PD-1 expression [25]; we have found that higher infiltration of CD4+ T cells but not CD8+ T cells was associated with higher PD-L1 expression on lymphocytes irrespective of their distribution in TME. The gene discussed is CD4; the disease is non-small cell lung carcinoma.