This phase IV study is hoping to determine if examining the microbiome in non-small cell lung cancer, immunotherapy naive participants can predict the effectiveness of immunotherapy treatment as well as determine ahead of time adverse events and their severity. In addition, the investigator will look into microbiome changing modifiers.

Inclusion Criteria:

• Must have tumor tissue biopsy-proven to be NSCLC
• Must have a target lesion to evaluate treatment response
• Immunotherapy naïve metastatic/advanced/recurrent NSCLC patients
• Will receive single agent anti-PD-1/PD-L1 therapy (e.g. pembrolizumab, nivolumab, atezolizumab, avelumab or durvalumab, etc.). Patients can be on other interventional trial if they will be receiving single agent anti-PD-1/PD-L1

Exclusion Criteria:

• Prior treatment with any forms of cancer immunotherapy
• Not competent to make medical decision, noncommunicative or noncompliant per treating physician's judgement
• Not English-speaking
• Patients that are pregnant
• Prisoners
• Students and employees
• Psychiatric illness/social situations that would limit compliance with study requirements

Immunotherapy naïve metastatic/advanced/recurrent NSCLC patients