Integrated sensing and communications (ISAC) has been identified as one enabling technology for B5G/6G communication systems and next-generation WiFi networks alike. Among the capabilities for environment perception such as localization and tracking, sensing of human activities using only radio frequency (RF) signals has in particular gained spotlights recently. Many research endeavors have proposed different solutions for supporting various applications including presence detection, user identification, pose estimation, gesture recognition, and breath monitoring. This talk aims to introduce the applications and technologies of device-free wireless human sensing for students, covering industry product and service as well as academic research and innovation.