**1. Introduction**

Immune checkpoint inhibitors targeting programmed death 1 (PD-1) and its ligand (PD-L1) have significantly changed the management of advanced non-small-cell lung cancer (NSCLC) in recent years [1]. Nivolumab, a fully human antibody directed against PD-1, has been approved for previously treated advanced NSCLC. Nivolumab was associated with significantly longer overall survival (OS) than docetaxel and had a good safety profile in squamous and non-squamous NSCLC in two pivotal phase III clinical trials (CheckMate 017 and CheckMate 057) [2,3]. Pooled analysis of long-term outcomes confirmed the significant clinical efficacy of nivolumab compared with that of docetaxel [4,5]. The value of nivolumab was assessed in prospective clinical trials, the results of which were required for drug registration. However, further real-world NSCLC population studies and evaluation of the value of nivolumab in clinical practice are necessary to select a subgroup of patients in whom clinical benefits are most likely. The patient population is much more diverse in clinical practice than in clinical trials. Negative prognostic factors are frequent issues in many cases, with poor performance status, brain or liver metastases, and elderly age being the most common. Real-world data can also be used to identify additional prognostic factors that may be helpful in treatment decision-making. Some real-world data concerning nivolumab have recently been published, including those derived from the Expanded Access Program (EAP) and post-registration studies (data for nivolumab are more frequently published than data for atezolizumab and pembrolizumab). This paper aims to provide an

overview of the selected real-world studies on nivolumab and to describe predictive factors of value in clinical practice.
