During the pandemic I've really found the 'stay at home' not fun and used it as an opportunity to instead of going to work and visiting businesses to explore my neighbourhood on more walks and more bike rides.Those activities I need to have some music bopping to help keep me going and smiling and I just love my Pixel Buds. If I'm walking it's the OG Pixel Buds (great sound), if I'm biking / running it's the Pixel Buds 2020 (still good sound but way easier to skip tracks while moving faster).
So, where would they go from the latest iteration? No clue, I can't really think of any big improvements they might want to make, and it's not really been a year since the last, so it feels a little 'soon' (it was like 2 years between the others)...
...but, there is filings with the FCC that show Google has 2 applications that may fit the bill.
Check out Android Police's article: https://www.androidpolice.com/2021/03/24/google-seems-to-be-working-on-a-new-set-of-pixel-buds/