Within the UPMC system, approximately 2,300 patients received PD-1/PD-L1 therapy for a variety of advanced solid tumors within the past year. It is anticipated that this number will increase as the clinical indications for treatment with these agents also increase. The investigators conducted a survey of 60 Medical Oncologists within the UPMC system regarding their interest in a trial that will attempt to address the question of optimal length of PD-1/PD-L1 treatment. Fifty-two (86.7%) physicians indicated that they would participate in a clinical trial that had a primary goal of determining whether it was feasible to stop immunotherapy after 1 year of treatment.