Another time jump has occurred on The Walking Dead, this time between the season 9 finale and the season 10 premiere - and a lot clearly happened during that time. Last season, there were three different time jumps that catapulted the zombie series beyond what fans were used to seeing and into a new era. The first time jump was 1.5 years, and that was between the season 8 finale and the season 9 premiere. It was done to show the deterioration of the world.
A second time jump - the really big one - was six years. It came as somewhat of a shock to viewers since it was done at the end of the same episode that Andrew Lincoln exited the series and Rick Grimes disappeared (or "died", as everyone in the show believes). Lauren Cohan had also left The Walking Dead between that time, though she's now slated to return in season 11. The final time jump happened in the season 10 finale, with the season changing to winter. It's unclear exactly how long the time jump was, but it stands to reason that it was only a few months.
Now, in The Walking Dead season 10 premiere, "Lines We Cross", it's revealed that another few months have passed on by between seasons. It's springtime now instead of winter and the Coalition are working to ready themselves for another attack, should the Whisperer War begin. Beyond that, Carol and Ezekiel's relationship seems to have soured, though that's presumably because of Henry's death at the fair. So instead of working with everyone to train, she left on an expedition.
Part of Michonne's story arc from the comics has been taken over by Carol in the TV series, which means that Carol is the one leading a solitary life aboard a boat. Given the welcome Carol receives, she must have been gone for quite some time, but whether returns to the high seas or stays back and fights the Whisperers with the rest of the Coalition remains to be seen.
While the state of affairs at Oceanside has been progressing quite smoothly, things at Alexandria are slightly different than they were before. For instance, Negan is now allowed outside of his cell for certain hours of the day; he tends to the garden during that time, perhaps due to his efforts saving Judith in the storm in the season 9 finale, but he's still very much a prisoner.
Elsewhere, a sitcom appears to be brewing in taking care of Rosita and Siddiq's baby, Coco, who was born sometime in the time jump. A deal was struck last season for four people - Rosita, Siddiq, Gabriel, and Eugene - to help take care of the baby since Siddiq is Coco's biological father but Rosita has been in a relationship with Gabriel; Eugene just wanted to help out. So all four of them passing Coco like a baton in season 10 may or may not become a bigger plot point down the line.