Immune checkpoint inhibitors (ICIs), a class of drugs that promote patient’s own immune cells called T cells to fight cancer, have revolutionized the care of cancer patients over the past decade.  But there remains a critical need for development of biomarker platforms to monitor patient response to cancer immunotherapy. Our laboratory has developed a novel immune cell specific exosome platform that enables noninvasive, dynamic, molecular window into the immune cell response to cancer immunotherapy. Translation of this platform to the clinical setting would mark a breakthrough technology in the field of cancer diagnostics.