This article reviews existing surveys and literature on holographic video communication, remote telepresence, and interaction. We first analyze the characteristics, key challenges, scenarios, and emerging applications of holographic video. Based on this analysis, we introduce HoloCom, a cloud-edge collaborative rendering architecture for large-scale communication and cross-platform interaction. The architecture supports mixed heterogeneous 3D content interaction, networking, and resource scheduling. Specifically, HoloCom incorporates two key methodologies using reinforcement learning techniques: quality of experience (QoE)-aware transcoding and system resource management. The QoE-aware transcoding method renders 3D videos into 2D views based on client network conditions and user viewports. The resource management method schedules transcoding tasks across cloud and edge servers to improve task execution efficiency. We implement HoloCom in a prototype system for museum interpretation, consisting of a cloud server, two edge servers, and three user devices. Evaluation results demonstrate that HoloCom achieves adaptive transcoding capabilities across heterogeneous devices and significantly reduces resource overhead for multi-user interactions, leading to a 23 percent improvement in average QoE and a 31 percent reduction in job delay. Finally, we outline future research directions and summarize the implications of the research.