When a player cannot make a legal move but is not in check, a stalemate exists. The match has ended in a draw. Neither player wins and neither loses.
In this illustration, the white knight moves from d2 to c5. Black is not in check, but cannot legally move either of its pieces. The black bishop at b9 is blocking check by the white rook and cannot be moved. All four of the hexes within the black king's reach are under threat by White's bishops, knight and/or rook. This match has ended in stalemate.