Inclusion Criteria:  [Immunotherapy group]  Male and female patients must be at least 19 years of age. Patients with histologically confirmed NSCLC Patients on palliative therapy for recurrence after surgery or de novo advanced and metastatic disease Patients receiving reimbursed immunotherapy as a second-line therapy (in case of targeted therapy, patients receiving immunotherapy after targeted therapy-platinum-based chemotherapy) Patients who provided written informed consent for the study (including the secondary use of the study data and sharing with third parties) [Cytotoxic chemotherapy group] Male and female patients must be at least 19 years of age. Patients with histologically confirmed NSCLC Patients on palliative therapy for recurrence after surgery or de novo advanced and metastatic disease Patients receiving reimbursed cytotoxic chemotherapy as second-line therapy after failure of platinum-based chemotherapy Patients who provided written informed consent for the study (including the secondary use of the study data and sharing with third parties)  Exclusion Criteria:  [Immunotherapy group]  Patients receiving immunotherapy without reimbursement Patients who do not provide consent to the study [Cytotoxic chemotherapy group] Patients receiving cytotoxic chemotherapy without reimbursement Patients who do not provide consent to the study