RecruitingPhase 2Drug trialStudy of Healthy Donor FMT (hdFMT) and Pembrolizumab in Relapsed/Refractory (R/R) PD-L1 Positive NSCLCThis study is to determine if Healthy Donor FMT (hdFMT) improves the body's ability to fight cancer in patients with relapsed/refractory PD-L1 Positive NSCLC.