Solid tumors pose significant challenges in cancer diagnosis and treatment due to their complex microenvironment and heterogeneity. Functional nanohybrids, integrating multiple components for targeted imaging and therapy, have emerged as a promising approach for solid tumor theranostics. This chapter explores the design and development of nanohybrids, such as lipid-polymer, metal-organic frameworks, and exosome-based systems, for enhanced tumor accumulation, controlled drug release, and synergistic therapeutic effects. The chapter discusses strategies to overcome biological barriers, optimize pharmacokinetics, and improve tumor penetration. Case studies demonstrating the efficacy of nanohybrids in preclinical models of solid tumors are presented. The chapter concludes by highlighting the potential of functional nanohybrids in advancing personalized cancer management.