## 1 Introduction  
The rapid advancement of digital technologies has fundamentally transformed how we interact with information, make decisions, and perceive our environment. The integration of emerging and disruptive technologies (EDT), such as VR, AI, and the IoT, continuously deliver new technological advancements, revolutionizing the industry, and seamlessly connecting physical and digital worlds. These three EDT technologies, individually impactful, hold immense synergistic potential when combined. VR creates immersive environments that enhance user engagement and understanding; AI drives intelligent decision-making through advanced data processing and predictive analytics, supports intelligent interactions between humans and machines, and generates content via dialogues in a fully automated manner; and IoT enables the real-time collection and communication of data by creating vast networks of physical devices. Together, these technologies unlock opportunities for innovation across multiple application domains. In recent years we have witnessed a significant progress in each of these technologies independently. VR and eXtended reality (XR) in general have evolved from simple stereoscopic displays and basic digital augmentations to sophisticated systems capable of providing highly immersive experiences [1; 2], with applications ranging from education [3; 4] and entrainment [5] to professional training [6; 7] and therapeutic interventions [8]. In the past five, years, AI (genAI, conversational AI, computational AI, symbolic AI, neurosymbol AI) has seen unprecedented growth [9], driven by significant academic and industry contributions. The development of conversational AI and large language models (LLMs) has transformed everyday human-computer interactions [10; 11], enabling more natural and intuitive communication while also assisting people by simplifying tasks in a variety of fields [12]. Additionally, computational AI demonstrated remarkable capabilities in pattern recognition, decision-making, and autonomous control, particularly through advances in machine learning and neural networks. Finally, IoT has expanded exponentially, with billions of connected devices generating vast amounts of data and enabling real-time monitoring and control of physical systems [13]. The current technological landscape also reveals several emerging trends that highlight the timeliness of this review. The rise of DTs, which combine IoT sensors with AI-driven simulations and VR interfaces, demonstrates the practical value of integrating these technologies. Similarly, the growing interest in meta-verse applications and immersive collaborative environments underscores the need for a better understanding of how these technologies can be combined/integrated effectively. Despite the undoubtful progress and importance of the individual EDTs, the integration of these three technologies remains relatively unexplored. A significant portion of the research focuses on VR, AI, or IoT in isolation or in limited pairings [14; 15; 16], neglecting the synergistic possibilities of their combined usage. Additionally, many studies emphasize theoretical frameworks rather than real-world implementations, leaving critical questions about feasibility and practical challenges unanswered. This paper presents a systematic review that seeks to address these gaps by analyzing current research on the integration of VR, AI, and IoT technologies. Adhering to PRISMA guidelines, it focuses on studies with real-world implementations and working prototypes to provide actionable insights for researchers and practitioners. Specifically, this review aims to:  
* Identify the primary application domains of VR-AI-IoT integration. * Identify and analyze methodologies, tools, and frameworks used for combining these technologies. * Highlight unique advantages of their synergy. * Discuss key limitations and challenges that hinder practical adoption. * Offer directions for future research to advance interdisciplinary innovation.