Human skin is a large-area, multi-point, multi-modal stretchable sensor that has inspired the development of electronic skin for robots, enabling them to simultaneously detect pressure and thermal distributions. By improving its conformability, the application of electronic skin has expanded from robots to the human body such that an ultrathin semiconductor membrane can be directly laminated onto skin. Such intimate and conformal integration of electronics with human skin, namely, smart skin, enables the continuous monitoring of health conditions. In this paper, we report the recent progress of stretchable thin-film sensors that are developed by our team for application to robotics and wearables.