PDCD1 and lung cancer: Additional data showed that PD-L1+ lung cancer stem cells modified the metastatic lymph-node immune microenvironment in NSCLC patients, positively correlated with the percentage of Tregs, PD-1+ CD4+ T cells and Tim3+ CD4+ T cells, while negatively correlated with that of CD4+ T cells and CD28+ CD4+ T cells [28].