Patients with cancer that respond to immunotherapy benefit from prolonged and possibly indefinite progression free survival. Response rates vary across cancer types, with solid carcinomas generally being the poorest responders at between 10-20%. Understanding the differences between responders (the 10-20%) and non-responders (the 80-90%) could identify ways to improve response rates. My research investigates a specific composition of extracellular matrix (ECM) molecules which may explain the difference between responders and non-responders.