Examples

Black can deliver bishop and knight mate with Bh3#.
The knight on f3 guards the escape squares g1 and e1.

Black can deliver bishop and knight mate with Qa3#.
The knight on c3 guards the escape squares b1 and d1.
The bishop can be replaced with a queen on the diagonal, and the pattern remains the same.

Bishop and knight mate can also happen in the middle of the board:

Black can deliver bishop and knight mate with Bd5#.
The knight on d3 is guarding the escape squares c5 and b4.
The king helps and protects bishop and knight.