Avatar: Frontiers of Pandora was first announced in February 2017, and is a first-person open-world adventure set in the world of James Cameron's Avatar series. It's set to release in 2022. The game received a trailer that displayed a combat scene between humans and the Na'vi, but little was revealed about where the game fits into the Avatar universe.
Avatar: Frontiers of Pandora: When Does it Take Place?
On the game's page in the Ubisoft store, a description reads as follows:
"In this new, standalone story, play as a Na’vi and embark on a journey across the Western Frontier, a never-before-seen part of Pandora. Explore a living and reactive world inhabited by unique creatures and new characters, and push back the formidable RDA forces that threaten it."
The description alone doesn't tell players much about when Avatar: Frontiers of Pandora takes place, but we do know conflict between the Na'vi and the RDA forces began around 2134. As a "standalone story", it's possible the game won't be closely linked to the events of Avatar or Avatar 2, and will instead take place closer to the time when the conflict began.
It's impossible to say when exactly the game will take place before Ubisoft releases more information, so players should look out for more news and updates leading up to the game's release in 2022.