The second-line treatment options in clinical practice for immunotherapy progress are complex. Treatment strategies need to be selected based on different progression patterns. It is difficult to simultaneously explore multiple treatment modalities through previous clinical studies. Observational studies through real-world research can efficiently convert clinical practice data into clinical treatment evidence. This study aims to observe the treatment patterns and clinical outcomes of advanced NSCLC patients who received first-line immunotherapy checkpoint inhibitor treatment after progression, in order to provide guidance for the second-line treatment options for patients with first-line immunotherapy progress.