Microbiome in Immunotherapy naïve NSCLC Patients Receiving PD-1/L1 Blockade (MIP_NSCLC)

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