Bishop and rook pawn with the wrong-coloured bishop draw whenever the defending king reaches the corner. Count the race before anything else: if the king gets to h8 (or g7 in time), the game is over.
The fortress catalogue in this chapter collects the shapes every player should recognise instantly. The first is the wrong-coloured bishop. White's h-pawn promotes on h8, a dark square, and the bishop on a2 is light-squared, so it can never control h8. If Black's king reaches h8, White cannot win.