Evaluation of Efficacy and Toxicity of Nivolumab Monotherapy for Advanced Non-small Cell Lung Cancer After First-line Treatment Failure Based on Second-generation Sequencing and Liquid Chip Platform

Inclusion Criteria

• •Subjects must be willing and able to comply with the schedule of visits, treatment protocols, laboratory tests, and other requirements of the study.
• •PS \> 2, lung cancer in the elderly (less than 65 years old).
• •subjects' characteristics and target disease characteristics Histologically or cytologically diagnosed as NSCLC (SQ or NSQ) and with stage IIIB/IV tumors (International Association for the Study of Lung Cancer Staging Manual in Thoracic Oncology, Version 8) or multimodal therapy (radiotherapy, surgical resection) Subjects who relapsed or developed disease after radical chemoradiotherapy for locally advanced diseases.
• •Prior radiotherapy or radiosurgery must have been completed at least 2 weeks prior to starting study treatmen