 Nanomaterials have been used to improve the effectiveness of photothermal therapy, which uses near-infrared light to heat up and destroy cancer cells. Nanoparticles such as carbon nanotubes, gold nanorods, and graphene oxide sheets can be used to absorb the light and concentrate it onto the tumor site. Additionally, nanomaterials can also be used to deliver drugs directly to the tumor site or act as photoimmunological agents to activate immune responses against cancer cells. Furthermore, nanomaterials can be used as theranostic tools, allowing doctors to monitor the progress of treatment by tracking the concentration of nanoparticles in the body. This article was authored by Austin C. V. Doughty, Ashley R. Hoover, Eli Via Layton, and others.