The line comes from Overwatch, Blizzard's team-based hero shooter released in 2016, where Tracer, the game's fast-moving British pilot and cover hero, uses 'Cheers, love! The cavalry's here!' as one of her signature greetings. Players heard it constantly in matches, so it became shorthand for her cheerful, confident personality and spread through gameplay clips, edits and memes. It remains popular because it is instantly recognisable, short enough for a reaction, and carries a friendly, heroic energy that works far beyond the game itself.