
Spearhead has been a game mode in Warhammer: Age of Sigmar for the last few years. Effectively a compact and streamlined version of AoS, with pre-set army lists, it's a very fun and competitive system that's easy to pick up and play.
In theory, the skirmish game holds a similar function (though very different rules) to Kill Team, which is set in the Warhammer 40,000 universe. In practice, however, there's been confusion in some areas of the fandom about what Spearhead actually is, with some players not even realizing that it's a fully-fledged game in its own right, rather than a simple branding exercise for army sets, à la 40K Combat Patrols.