It is harder to mate with minor pieces then major pieces. It can take at least 30-40 moves to checkmate with a knight and bishop. Also, it would be called stalemate if there a bishop and king vs one king
It is easier to checkmate with major pieces than minor pieces because major pieces have more value in them, for example, a queen is worth 9 points and a rook is worth 5 points, while the knight and bishop are worth 3 points.
Here it took more moves to checkmate with rook than bishop, but it is much more easier to learn how to checkmate with rooks Below there are two-games that Hikaru Nakamura played (both of the games are very long)