Deals with basic rights of non-humans or other sentient beings other than the ruling one. Or how much a non-human can be considered a real person or have value as a person comparable to the main species (humans in most cases).
The first video game about Non-human rights was released on November 1994.
Square Enix has published all these games
This is not for cases where the issue is outright ignored.
Rating dissonance is not part of this tag either, such as games getting ESRB Teen rating if only non-humans are killed but jumps to Mature rating if they're human.