Some Maps are themed to match environments associated with one or more Legends. This also applied to crossover characters. This is simply a name given to the combination and not an actual advantage.
First appearing in the second season of the Battle Pass, there is a mission where you must win a game with a home field advantage. To do this, you needed to win as a Legend or Crossover character on their home field. However, winning a match with a Crossover character on the base Legend's home field, for example Jake (Kor) on Blackguard Keep, would not count towards the mission.
List of Home field advantages
The following is a list of some of the home field advantages in the game.
Crossover Home fields
The following maps are home field advantages only for crossover skins.
The following maps are gamemode exclusive but still have home field advantage.