Will Hades be available on Xbox Game Pass again in the future?

Not likely. Game Pass and other similar services stopped offering many deals like they used to for indie studios. I started using it again recently but it feels like so many games have been taken off, likely due to Game Pass not performing as well as they expected it to

If I had to guess I’d say it will be back on around the time Hades 2 leaves early access, if Hades 2 itself doesn’t come to GP.