Context Awareness refers to the use of context to provide task-relevant information and/or services to a user. The Holistic Framework for Human-Machine System (HMS) is an architecture based on multiple factors, including a surroundings consideration, to design Digital Twins (DTs). This paper discusses some of the research challenges in understanding the context and developing context-aware DT systems. In particular, the authors gave some solutions that can improve Human-Machines Systems (HMS), such as the use of human data, meta-data and peri-data or the definition of Capacity, Availability, Possibility levels. Finally, a critical discussion is brought to caution future designs of systems such as HMS in a high risk context.