Moreover, this consistent negative association between ED and PFS was evident across various subgroups (Fig. 2b), including the subgroups based on age (<65 years versus ≥65 years), PD-L1 expression (negative versus positive), NLR (<5 versus ≥5), male, smokers, lung squamous, stage IV, combination treatments and absence of brain/liver metastasis, among others. Here, CD274 is linked to metastasis.