Immunoadjuvants are crucial components of cancer immunotherapy that enhance immune responses against tumors. This chapter explores the underlying mechanisms and clinical uses of immunoadjuvants in cancer immunotherapy. Toll-like receptor agonists and STING agonists are two types of immunoadjuvants that activate immune cells and promote anti-tumor immunity. Cytokine-based immunoadjuvants have potential toxicity and off-target effects, but nanotechnology enables precision delivery to minimize these issues. Personalized approaches, biomarker discovery, and predictive modeling are important for optimizing treatment responses. Overall, immunoadjuvants are essential tools in cancer immunotherapy for generating strong and long-lasting anti-tumor immune responses. In conclusion, immunoadjuvants are critical components of cancer immunotherapy, playing a vital role in boosting strong and durable anti-tumor immune responses.