This project will leverage the clinical trials infrastructure of the National Clinical Trials Network (NCTN) to help develop a greater understanding of the mechanisms of immune-related Adverse Events (irAE) through supporting the ongoing development of a novel resource of tissues and gut microbiome samples from patients with irAEs. Analysis of samples will include stool microbiome metagenomics sequencing. Patients experiencing irAEs will have tissue, blood, and potentially stool collections obtained on an event-driven basis.