Immune checkpoint inhibitors have taken an important place in the field of oncologic immunotherapy, especially for patients in whom conventional treatment regimens have failed. Nivolumab prevents programmed cell death 1 (PD-1) and programmed cell death ligand-1 (PD-L1) binding, resulting in blockage of the inhibitory signal and thus facilitating an immunologic antitumor response. Nivolumab has been shown to be effective in thoracic malignancies, including non-small cell lung cancer (NSCLC). Here is a case of 52-year male patient with metastatic lung adenocarcinoma progressing after 4 cycles of chemotherapy. We started nivolumab q2 weeks therapy. Firstly, his dyspnea relieved, carcinoembryonic antigen (CEA) and C-reactive protein (CRP) levels regressed, and then their levels remained constant at a stable level. Radiologically stable response was seen. Progression was seen after about one and half year. Patient died in a short time after progression. In conclusion, this observation provides a strong indication of the potential value of immune checkpoint inhibitors for the management of metastatic lung cancers.