## 1 Introduction  
The integration of immersive and interactive human-to-data/information interfacing has become a critical element in numerous domains, including academia, education, biomedicine, and industry [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11]. Indeed, extended reality (XR) interfaces, whether in the form of virtual reality (VR), augmented reality (AR), or mixed reality (MR), are gaining widespread acceptance and are becoming a prevalent display mode [12; 13; 14]. These interfaces are fundamentally transforming how we perceive and engage with 3D data, finding applications in various sectors, such as medicine [15; 16; 17; 18; 19; 20; 21; 22; 7; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45;  
Powered by the ever-growing availability of powerful yet cost-effective hardware, new paradigms are emerging, such as the interactive immersion of several participants into holographic 3D data using different types of interfaces, such as head-mounted displays (HMD) and handheld devices (HHD) in synergetic activities or on-the-fly use of complex computational tools [15]. In addition, in a recent scholarly work, [PERSON] et al. [27] elaborated on the concept of immersive analytics, wherein VR serves as an important tool in the fields of analytical reasoning and, therefore, decision-making. One of the practical challenges and an important requirement in deploying modern human-immersion systems is providing computational power for on-the-fly processing and analytics [15; 28; 29; 30]. Holographic immersion systems perform a considerable number of calculations [17] to process and reconstruct a 3D mesh and hologram on holographic displays, which requires processing power [15; 31; 32]. Also, with the increasing integration of AI-driven models for real-time data analysis and diagnosis, providing more computational resources is vital to avoid data delivery delays [29; 30; 33; 34]. Moreover, interfaces need to provide an interactive and ergonomic experience for the viewers to ensure that their center of attention is on the actual data rather than operating the front end of the system. Providing such an environment requires high processing power, data exchange, and memory to retain the information of the holograms, which seems challenging to fulfill by the current generation of XR limited hardware capabilities. Therefore, to address this issue, system designs [15; 17; 31; 35; 36; 37] rely on external servers or processing units to perform these crucial functionalities to reduce resource utilization on the HMD or HHD. Multiuser synergy in XR environments requires sharing a massive amount of information regarding the XR scene in which users are able to interact. Digital worlds, such as the Omniverse, Metaverse, and Multiverse [38; 39], provide a VR environment for digital twins [40], where users make virtual presence in a virtual world and interact in a shared XR scene. Providing location-independent infrastructure in this multiuser paradigm is crucial and is accomplished by leveraging local or public cloud infrastructures. An example is the immersive experience of patients remotely using HMD or HHD in a treatment environment [40; 41]. In this study, we developed a highly available, reliable, modular, scalable, and interfaceable framework called Holo-Cloud. Holo-Cloud demonstrates the feasibility of a platform-independent framework to effectively address the increasing demand for computational resources and processing needs by XR applications. To enable current and future applications, this study had four primary directives that led to corresponding contributions. First, it was developed with cloud deployment as an inherently location-agnostic data immersion service for concurrent multiuser synergetic interactive immersion in multidimensional information. Second, server-based primary computing ensures the delivery of the required computational power for analytics and on-the-fly data processing to all users, regardless of the hardware capabilities and specifications of the locally employed HMD or HHD.