For years, M’Baku has battled Black Panther in the comics as Man-Ape, and that conflict will carry over somewhat to the Black Panther movie.
So far our only good look at M’Baku in Black Panther is when he’s holding up a Wakandan not of his tribe and yelling fiercely.
Despite being a Black Panther villain in the comics and clearly not the world’s biggest T’Challa fan in the MCU, M’Baku hasn’t been identified as one of the movie’s main antagonists alongside Erik Killmonger and Ulysses Klaue.
Given that M’Baku is confirmed to appear in Avengers: Infinity War, that rules out him being killed in Black Panther, so I suspect that during the latter half of the latter movie, M’Baku and T’Challa will strike up an uneasy alliance to stop Killmonger and Klaue.