No, League of Legends is not available on Xbox or any other console platform.
League of Legends is a PC-exclusive title developed by Riot Games. It has never been ported to PlayStation, Xbox, or Nintendo consoles. The game's complex controls, frequent updates, and competitive ecosystem are tailored specifically for keyboard and mouse on Windows and macOS.
If you're looking for similar MOBA experiences on consoles, you might explore games like Smite or Arena of Valor, which were designed with gamepad controls in mind.