This thesis presents the development of theranostic gold nanostars (GNS) for multimodality cancer imaging and therapy. Furthermore, it demonstrates that a novel two-pronged treatment, combining immune-checkpoint inhibition and GNS-mediated photothermal nanotherapy, can not only eradicate primary treated tumors but also trigger immune responses to treat distant untreated tumors in a mouse animal model. Cancer has become a significant threat to human health with more than eig