Killmonger's goals for Wakanda differed greatly from T'Challa's, and thus he sought to take T'Challa out and become the Black Panther.

Source: https://www.cbr.com/great-mcu-speeches/

This means that while Black Panther will be in a starring role, it won't actually be King T'Challa under the vibranium suit, but rather his grandfather, Azzuri.

Source: https://gamerant.com/black-panther-marvel-skydance-game-chadwick-boseman-wakanda-forever-new-version-setting-azzuri/

When Killmonger duels him for the titles of king and Black Panther, he impaled T'Challa through the chest and he nearly died.

Source: https://collider.com/black-panther-family-tree/

While T'Challa has faced off against a seemingly endless variety of villains in his time as Black Panther, that chapter of his life is quickly approaching its end.

Source: https://www.cbr.com/marvel-voices-wakanda-forever-nameless-warrior-future-foretold-marvel/