The Technical Cooperation Program (TTCP) Contested Urban Environment (CUE) 2017 Experiment was con- ducted to explore and evaluate technologies that can enhance close combat capabilities in contested urban environments through the exploitation of airborne intelligence, surveillance, and reconnaissance (ISR) capabilities and ground sensors. This paper focuses on case studies and an evaluation of the interoperability standard between all coalition systems chosen for this event, OSUS. The Open Standard for Unattended Sensors (OSUS) is an interoperability architecture for unattended ground sensor (UGS) controllers. The U.S. Army Research Laboratory continues to develop and improve the OSUS standard, and as part of research on interoperability, participates in a variety of experiments, demonstrations and exercises. The United States provided ground sensors and a Command and Control (C2) station, Australia provided airborne sensors and a C2 station, and Canada provided C2 workstations along with a suite of ground sensors. Partner nations attended an OSUS workshop early in 2017 at the ARL, Adelphi. MD. USA campus. This provided a chance for hands-on instruction in OSUS fundamentals and the programming of OSUS controllers and interfaces. The difficulty of adding an OSUS interface into a sensor or C2 system, the challenges and benefits of using OSUS during a coalition event, and the overall effectiveness of the implementation for this specific experiment were examined. The average amount of time to implement an OSUS interface for a sensor or a C2 station was two weeks. The integration phase was fast and seamless after a single day of integration and testing, five of six tested systems were fully operational and the sixth was missing only one function. Several shortcomings of the data model were uncovered, which was to be expected as the data model was developed for Unattended Ground Sensors (UGS) and not airborne platforms. Overall, OSUS provided a robust and reliable means of communication between each of the systems. TTCP/CUE is an ongoing study and a similar event is planned for Montreal, Canada in 2018.