<p>- The swift expansion of Internet of Things (IoT) nodes in contemporary cities is catalyzing a shift in urban connectivity and heightening the demands placed on network technologies. This requires enhancements in spectrum and energy efficiency. Cognitive radio (CR) and advanced multiple access techniques present effective solutions for improving spectral utilization and addressing the challenges posed by the dense deployment of IoT devices. At the same time, radio frequency energy harvesting (RFEH) offers a sustainable method for powering IoT nodes by harnessing ambient RF energy, thereby decreasing reliance on conventional energy sources. This article presents a thorough bibliographic review of recent advancements in CR-enabled RFEH systems for beyond 5G (B5G) networks, emphasizing hybrid multiple access schemes. This examination delves into the ways in which these integrated technologies can greatly improve energy efficiency and suggests a sustainable framework to facilitate scalable IoT communications. This work brings together existing research initiatives and highlights significant challenges and opportunities within this developing field.</p>