Squamous cell carcinomas of the head and neck (SCCHN) are a group of cancers that develop from a thin, moist layer of squamous cells—called a mucosal surface—that line the inner structures of the head and neck, such as the mouth, nose, and throat. Cancer cells use a variety of ways to avoid the body’s natural defense—the immune system—to continue to grow, invade, and spread. In SCCHN, molecular interactions between PD-1 on our immune system’s T-cells and PD-L1 on cancer cells drive whether or not the body’s immune system will attack a cancer cell. This program will look at the cellular underpinnings of SCCHN, as well as agents—known as checkpoint inhibitors—that target PD-1 or PD-L1 for improved management of this condition.