>>51847336History suggests that Niantic likes adding new Rocket features during the fall rotation:
>Fall 2019: Team GO Rocket Leaders and Giovanni>Fall 2020: Rocket Leaders now reward Strange Eggs>Fall 2021: ...2021 actually didn't really add a new feature, probably because we were a year and a half into the pandemic and they just wanted it to be over with at that point. I guess you could technically say this was the first event to debut Shadow Johto legendaries and Rocket tie-ins as part two to events. I would be more surprised if they didn't add a new feature/boss this year, considering they've already added a ton of stuff now that the pandemic is done in their eyes.
What if it's the debut of Team Magma/Team Aqua? They'd be harder/less common than Team GO Rocket in the wild, the team leaders would give you a constant chance at Shadow shiny Numel/Carvanha, and the crime bosses would give you an encounter with Shadow Groudon/Kyogre. Would be pretty disappointing if Giovanni is the only crime lord we ever see in this game. 