Background: Although the administration of immune checkpoint inhibitors (ICIs) and antiangiogenic agents in advanced non–small-cell lung cancer (NSCLC) has been well established, evidence supporting the combination of immune checkpoint inhibitors plus antiangiogenic drugs in previous treatment patients with advanced NSCLC is insufficient. We aimed to investigate the efficacy and safety of nivolumab combined with recombinant human endostatin (rh-Endostatin) as second-line or later treatment for advanced NSCLC. Methods: In this prospective and multicentre phase 2 trial we enrolled patients with advanced NSCLC who had not responded to standardized first-line treatment regimen from two cancer centres in China. Eligible patients were those aged 18-75 years without ICIs in first-line treatment who received nivolumab (3mg/kg, intravenous drip, day 1) every 2 weeks and rh-Endostatin (30 mg, 24-hour continous intravenous infusion，day 1–7) every 4 weeks till disease progression or discontinuation. The primary end points were objective response rate and safety. This study is registered with Chinese Clinical Trial Registry, number ChiCTR1900023664. Results: A total of 35 patients (median age, 60 years; range, 37-72 years) received nivolumab and rh-Endostatin. Median previous treated line of eligible patients was 2 lines (range, 1-7 lines). Patients received a median of 2 cycles of therapy (range, 1-14 cycles). Eleven of 33 evaluable patients achieved confirmed partial response with an objective response rate of 33.3% (11/33, 95% confidence interval [CI]: 17.2% – 49.4%) and disease control rate of 60.6% (20/33,95%CI:43.9%–77.3%). Median follow-up was 8.2 months (range: 0.9 –17.1). Median progression-free survival was 7.1 months (95% CI: 1.2m–13.0m), median overall survival was not reached and the 6-month overall survival rate was 54.5% (95% CI:37.6%–71.4%). The predominant grade 1-2 adverse events were thyroiditis, arrhythmia, hypertension. The grade 3 treatment-related adverse events were pneumonitis (3/35, 8.6%), hypertension (1/35, 2.9%) and atrial fibrillation (1/35, 2.9%), respectively. No grade 4 or 5 treatment-related adverse events were observed. Conclusions: To the best of our knowledge, this is the first prospective study that assessed nivolumab combined with rh-Endostatin as second-line or later treatment in pretreated patients with advanced NSCLC. In view of its encouraging efficacy and safety profile, nivolumab plus rh-Endostatin represents a promising treatment regimen in this patient population. Clinical trial information: ChiCTR1900023664.