Evaluating Length of Treatment With PD-1/PD-L1 Inhibitor in Advanced Solid Tumors

Inclusion Criteria: * All patients must have an advanced solid tumor malignancy (specifically NSCLC, bladder, HNSCC, renal, melanoma, cervical, Merkel cell, MMR/MSI \[colon, rectal, cholangio, esophageal, ovarian, uterine\], anal, gastric and GE junction, hepatocellular, triple negative breast cancer) that is being treated with a PD-1/PD-L1 inhibitor including pembrolizumab, nivolumab, atezolizumab, durvalumab, or avelumab according to standard of care treatment. * Patients who initially started treatment with another agent in combination with the PD-1/PD-L1 inhibitor, i.e. chemotherapy, ipilumumab, are eligible. * Patients must have at least stable disease as evidenced by scans performed within 6 weeks of randomization. * Signed Informed consent allowing randomization to stopping immunotherapy at 1 year ± 6 weeks versus continued treatment beyond 1 year. * Patients can have measurable or non-measurable disease per RECIST v1.1. * Patients cannot be enrolled in a clinical trial. Exclusion Criteria: * Patients with documented progressive disease prior to randomization. * Patients with an immune-related toxicity preventing the continuation of treatment beyond 1 year at the treating physician's discretion.