General-Purpose Input/Output (GPIO) is a specialized skill that involves the use of pins on a microcontroller or computer to interact with external devices such as sensors, motors, and LEDs. GPIO programming requires knowledge of programming languages such as C, Python, and Rust, as well as an understanding of electrical circuits and signals. The ability to work with GPIO is a valuable skill for developers and engineers, particularly in the field of Internet of Things (IoT) and robotics, where external devices must be controlled and monitored through the use of GPIO pins.