Nano-immunotherapy leverages advanced nanocarrier systems to overcome limitations of conventional immunotherapies, providing precise immune modulation through targeted delivery of antigens, immunomodulators, and genetic material. Lipid-based, polymeric, inorganic, and hybrid nanocarriers enable controlled release, enhanced bioavailability, and site-specific immune activation, optimizing therapeutic efficacy while minimizing systemic toxicity. Pharmaceutical formulation strategies, including particle engineering, surface functionalization, and payload optimization, are critical to enhancing immune targeting and pharmacokinetics. Clinically, nano-immunotherapeutics have demonstrated remarkable success in vaccines, cancer immunotherapy, and genetic disease treatment, exemplified by mRNA-LNP COVID-19 vaccines and liposomal chemotherapies. Despite challenges in manufacturing, stability, and regulatory approval, emerging trends such as AI-driven design, personalized formulations, and integration with gene-editing technologies forecast a future of precision nano-immunotherapy with broad clinical impact.