This chapter introduces Urbanimmunology, a game-changing discipline inspired by human immune intelligence (HII) that aims to reshape urban and social systems with the ability to adapt and respond to disruptions. It begins by exploring the forces behind the Great Acceleration and the urgent, high-stakes demands of planetary health, emphasizing the need for innovative solutions to urban and social challenges. The chapter then highlights the brilliance of the human immune system, showcasing its remarkable intelligence. Drawing powerful parallels between immune responses and urban and social dynamics, Urbanimmunology emerges, with the core functions of the immune system providing a dynamic framework for urban and social systems. The chapter delves into the significance of this emerging field, revealing its broad impact and offering new perspectives on urban and social development challenges. From this discipline, a bold approach to policymaking process management, called DIRECT, is developed. The concept of the HEARTY city, with its “immune genes,” is also explored, linking it to this discipline while addressing the theoretical challenges facing cities and society. The chapter concludes with a visionary outlook, charting an ambitious path for the future.