PDCD1 and lung cancer: In patients with LMs, compared with chemotherapy alone, PD-1/PD-L1 inhibitor plus chemotherapy could decrease the risk of progression by 31% and risk of death by 21% (HR = 0.69;95%CI,0.58–0.81; and HR = 0.79; 95%CI,0.62–0.80, respectively), suggesting that lung cancer patients with and without LMs could obtain comparable efficacy.