Objective To analyze the efficacy and safety of programmed cell death 1 (PD-1) and programmed cell death ligand-1 (PD-L1) immunotherapy combined with docetaxel chemotherapy in the treatment of advanced retreatable non-small cell lung cancer (NSCLC). Methods The study retrospectively analyzed clinical data of 280 patients with advanced retreatableNSCLC treated between July 2017 and July 2019. Patients treated with docetaxel chemotherapy were included in the control group (n=130), while those treated with PD-1/PD-L1 immunotherapy combined with docetaxel chemotherapy were included in the observation group (n=150). Clinical effects, tumor markers ［cytokeratin 19 fragment 21-1 (CYFRA21-1), Carcinoembryonic antigen (CEA)］, immune function, the incidences of adverse reactions and 1-year overall survival and progression-free survival (PFS). Results The RR of the observation group was higher than that of the control group (58.67% VS 38.46%) (P＜0.05). After treatment, serum CYFRA21-1, CEA and CD8+levels in the observation group were lower than those in the control group, while CD3+, CD4+, and CD4+/CD8+were higher than those in the control group (P＜0.05). The PFS survival rate and 1-year survival rate in observation group were higher than those in control group (P＜0.05), and the incidence of adverse reactions was lower than that in the control group(20.00% VS 42.31%) (P＜0.05). Conclusion PD-1/PD-L1 immunotherapy combined with docetaxel chemotherapy is effective in the treatment of advanced retreatable NSCLC, which can improve serum CYFRA21-1, CEA levels, immune function and survival rate, with high safety.