Warning! SPOILERS for The Walking Dead season 10 premiere ahead!
The Walking Dead season 10 premiere has Carol returning from a voyage at sea, and it's a direct reference to a role Michonne has in the comics. AMC's The Walking Dead has never been a strict adaptation of the comics, but the series will often pull inspiration from them all the same. In this instance, The Walking Dead is taking elements from Michonne's comic book story and transplanting them to Carol - and for good reason.
Following a very well-received season 9, The Walking Dead season 10 will see its survivors finally go to war against the Whisperers. There have been encounters with them already, including one that saw several survivors killed and their heads placed on pikes to mark the border of Whisperer territory. This chilling incident is another taken directly from The Walking Dead comics, but again, it's slightly altered. One of the changes is the identities of the victims, while another is the timing of the murders, and both are part of the reason why it's Carol and not Michonne who steps off that fishing boat in The Walking Dead's season 10 premiere.
In the season 10 premiere, "Lines We Cross," it's revealed Carol has been captaining a fishing boat that sails from Oceanside and is often at sea for weeks at a time. She's taken on this new responsibility because her grief over her son, Henry's murder (one of the victims whose head marked the border) has created a rift between Carol and Ezekiel and she's keen to be alone. In The Walking Dead comics, it's Michonne who chooses this solitary lifestyle for similar but not entirely the same reasons. In her case, Michonne is also running from a failed relationship with Ezekiel, but her reason for doing so stems back to the regret she feels for abandoning her daughters during the initial outbreak. Taking this portion of Michonne's comic book story and giving it to Carol makes a lot of sense for The Walking Dead season 10. For one, the TV show's version of Carol has already displayed a penchant for running away from her problems, so for her to seek solace alone at sea following such a tragedy is perfectly within character.
Also, it's Carol and not Michonne who has the relationship with Ezekiel (for now anyway), so again, giving her this role in the story fits as a loose adaptation of what happens in the comics. And finally, AMC's The Walking Dead has played around with the timing of events, flipping the order in which certain things occur. In the case of the comics, the infamous 'heads on pikes' murders come after Michonne returns from sea, only later discovering that Ezekiel has been killed. On TV, though, Henry's murder is what sends Carol to sea, and her return is instead setting her on the path of revenge against Alpha and the Whisperers.
The Walking Dead season 10 is also the final season for Danai Gurira's Michonne and handing off a portion of her comic book arc to Carol helps establish that once Michonne is gone, it'll be Carol - along with Daryl and the returning Maggie - who will be the de facto leads of The Walking Dead. We don't yet know how Michonne will exit the show, but seeing as an upcoming romance between Ezekiel and her has been teased, perhaps The Walking Dead will again loosely adapt its source material and have Michonne, not Ezekiel, be another of The Whisperers' victims. However it happens, Michonne is leaving this season and by giving Carol a portion of her story from the comics, The Walking Dead season 10 is setting the stage for Carol to take on an even larger role.
The Walking Dead season 10 continues next Sunday, October 13th with "We Are the End of the World" at 9/8c on AMC.