As cities evolve toward City 5.0, retrofitting urban structures with intelligent systems has become essential to achieving sustainability, digital transformation, human-centricity, and resilience. This study presents an integrative literature review exploring the role of emerging technologies, including IoT, digital twins, robotics, blockchain, and AI, in retrofitting urban infrastructure. The study highlights how these technologies enhance energy efficiency, urban connectivity, disaster adaptability, and public engagement, making cities more adaptive and resilient to future challenges. Despite the promising potential of intelligent retrofitting, several barriers persist, including financial constraints, technological interoperability issues, and regulatory hurdles. The complexity of integrating smart technologies into existing urban infrastructure requires policy frameworks, investment strategies, and interdisciplinary collaborations to ensure seamless adoption. Overcoming these barriers necessitates public-private partnerships, technological innovation hubs, and policy incentives to accelerate the transition toward intelligent, self-sustaining urban environments. This research underscores the importance of data-driven urban planning, predictive maintenance, and decentralized infrastructure solutions in shaping future cities. Public engagement, participatory urban planning, and knowledge-sharing initiatives are crucial in aligning retrofitting strategies with community needs. Ultimately, integrating intelligent systems into urban retrofitting is key to ensuring that future cities remain sustainable, technologically advanced, and socially inclusive, paving the way for efficient, resilient, and adaptive urban development.