Will the same xbox game pass subscription cover both xbox one and xbox series x

Game Pass Core is just an online subscription, so if you purchase Game Pass for Xbox, you do not lose Game Pass Core, you will have both subscriptions at the same time. If you cancel Game Pass Core, then you will lose your Xbox One/Series X|S Games with Gold Games.

The subscription can be used on any Xbox One or Series S/X that you sign into. As long as you're using the same account on both consoles, you'll have access to the subscription.

Good news!

Game Pass ultimate will work with both your Xbox One and Xbox Series X.

Since you have Ultimate, it also works on your PC (if you have one) as well.

No need for a new subscription. Just log into the same Microsoft account on both consoles.

You’re welcome and you’re correct. But Xbox Game Pass is not available for Xbox 360, it’s only available on Xbox One as well as Xbox Series X|S and that’s why you’re getting the error.

If you have an Xbox One or Xbox Series X|S you will be able to use the subscription both on PC and Xbox.

If the game just says Xbox Series X on the Game cover, then no, it will not work on the Xbox One. If, it says Xbox Series X & Xbox One on the cover, then it will work.