If there are other mystery cast members here as well, it could only further point to a significant event taking place.
If this is part of Thor’s vision being realized, it could also be possible that Tony’s vision of the Avengers dead in the sky could be coming true as well.
If this is the case, the large presence of stars could be a result of them all being dead or an attempt to rescue/resurrect a select few fallen members.
Even if this is not the case, the setting could be the eventual secret hideout for whatever heroes remain as they look to strike back against Thanos.