This doesn''t even classify as a slogan. It's not a unique phrase and 'discover your next ...' is as generic a marketing line as they come.
It is generic, but Game Pass has been using it for several months now (I distinctly remember it being mentioned at E3). It is their slogan, plastered everywhere and was inside ads. It's kinda hilarious they took the exact same words and used them, but it's no big deal. Just... there's no way nobody knew MS is already using the exact same phrase. I mean, imagine if Samsung launched a new phone now with a dark mode, and they used the exact same slogans Apple used for theirs. It's not copyright infringement but it's funny.