Which publisher published Overwatch?
which publisher refers to publisher_name; Overwatch refers to game_name = 'Overwatch';
SELECT T3.publisher_name FROM game AS T1 INNER JOIN game_publisher AS T2 ON T1.id = T2.game_id INNER JOIN publisher AS T3 ON T2.publisher_id = T3.id WHERE T1.game_name = 'Overwatch'