Inclusion Criteria:  Inclusion/exclusion criteria of J-TAIL-2 study is to be applied.  <non-small cell lung cancer cohort>  Patients 20 years of age or older at the time of signed consent. Patients with unresectable, advanced and recurrent non-small cell lung cancer. Patients who are scheduled to start atezolizumab combination therapy in clinical practice, based on the atezolizumab package insert and the Optimal Clinical Use Guideline. Patients who signed informed consent form before enrolling the study. The consent from a legally acceptable representative is required for the patients with uncertain capacity of judgments.  <extensive disease small cell lung cancer cohort>  Patients 20 years of age or older at the time of signed consent. Patients with extensive disease small cell lung cancer. Patients who are scheduled to start atezolizumab combination therapy in clinical practice, based on the atezolizumab package insert and the Optimal Clinical Use Guideline. Patients who signed informed consent form before enrolling the study. The consent from a legally acceptable representative is required for the patients with uncertain capacity of judgments. However, the samples of dead cases can be used for the analysis of immune microenvironment of small cell lung cancer by disclosing information on this study.  Exclusion Criteria:  <non-small cell lung cancer cohort>  1. Patients who are unsuitable for enrolment into the study by the investigator's judgment.  <extensive disease small cell lung cancer cohort>  1. Patients who are unsuitable for enrolment into the study by the investigator's judgment.