Commercial Vehicle (CV) market is growing rapidly with the advancement of Software-Defined Vehicles (SDVs), which provides greater level of flexibility, efficiency and integration of AI & cutting-edge technology. This research provides in-depth analysis of E&E architecture of CVs focusing on SDV based technology, which represents the transition of hardware focused to a more dynamic, software focused methodology. Research begins with the fundamental concepts of E&E architecture in CVs including virtualization, centralized computing, feature based ECU, CAN and modular frameworks which are then upgraded to meet various operational and customer requirements. The capacity of SDV based architecture designs to scale to handle heavy duty commercial vehicles is a primary focus, also to ensure the safety and security, to defend against possible vulnerabilities. Furthermore, the integration of real-time data processing capabilities and advanced E&E architecture is proposed with the features available in the current and potential future market. We also examine current and upcoming market trends in CV related to the E&E architecture and talked about the advanced features like OTA, fleet management, telematics and much more. This research focuses on adding SDV features to upcoming CVs with the goal of improving vehicle performance. In the future scope, consideration includes the integration of autonomous driving technology, growing significance of cloud and edge computing technology in enhancing commercial vehicles' decision-making capabilities. Through this research, it offers a comprehensive understanding of how SDV architecture is set to revolutionize the commercial vehicle industry which provides insights into how it will contributes to CVs become more automated, connected and efficient.