*2.1. Search Strategies and Study Selection*

We conducted a systematic search in PubMed to identify all eligible trials from inception until 1 January 2020, with no start date limit applied. Literature search terms used were "non-small cell lung cancer" (or "NSCLC"), "chemotherapy", "pembrolizumab", "nivolumab", "atezolizumab", "durvalumab", and all terms related to clinical trial registration (ClinicalTrials.gov, EU Clinical Trials Register, ISRCTN, and ANZCTR). An additional search of abstracts presented at the American Society of Clinical Oncology (ASCO), European Society for Medical Oncology (ESMO), American Association for Cancer Research for Medical Oncology (AACR), and World Conference on Lung Cancer (WCLC) was also performed.
