Sensing has emerged as a key feature of modern wireless communication systems and networks. Traditionally, advances in the design, optimization and deployment of sensing and communication systems have evolved somewhat independently of each other. In recent times however, we are beginning to appreciate the benefits offered by the synergy between sensing and related areas in communication, largely driven by modern applications such as autonomous driving, motion sensing in health applications, target detection and localization in smart cities, dual-function radar and communication systems, and optimal beam selection and alignment in millimeter wave communication. We are pleased to announce that in this special issue we have collected exciting recent results on a broad range of different domains and applications that rely on sensing, with a focus on fundamental contributions that explore the performance limits of sensing problems and offer innovative solutions.