There's a very high chance that some characters may return in some way in The Last Of Us Part II. The game will be putting players in control of Ellie now, with Joel being teased as a supporting character. Ellie is now out for revenge after an event that occurs that takes away someone she deeply cares about.
The theme of the game seems to follow the idea of revenge very deeply, and will hopefully even dive into some of the unanswered questions of the first game. Ellie and Joel both came across some interesting characters on their journey in The Last of Us. Here we'll be ranking every character in the first game based on the likelihood of their return.
10 Henry
Henry was the older brother of Sam and formed a pretty strong relationship with Joel. They were able to trust each other and seemed to want to work as a team. The following morning after reaching a safe place to rest, Ellie goes to check up on Sam and finds that he's been turned. The whole scene plays out extremely intensely with Henry struggling to figure out what to do. He still feels like he has to protect his brother, even though he's turned. Henry makes the right choice in shooting Sam to help Ellie but ends up killing himself. It's very unlikely he'll make a return through flashbacks in the sequel.
9 Sam
Sam was the younger brother of Henry that appeared briefly in one of the saddest moments of the game. Ellie forms a relationship with Sam and helps him see the good that he's doing and make him realize it's okay to be scared. They have a really deep conversation about their fears and the infected still being people. A small glimpse of a bite on Sam's leg is shown before cutting back to Ellie. She finds him, now turned into an infected. It's really unfortunate as things at this moment were starting to look up and Ellie finally had a new friend around her age. He's definitely unlikely to make a return, even for a flashback.
8 Bill
Bill is the first new character players meet after Tess's death and the beginning of Joel and Ellie's journey. He's a very resourceful survivor that has a bunch of traps set up around his home so it's possible he could still very well be alive in The Last Of Us Part II. Even if he's alive, it's highly unlikely that he will return in the sequel as his story wouldn't really fit well with Ellie's personal quest for vengeance. He was more of a character suited for Joel's storyline and at the end of that sequence, he didn't seem to ever want to be bothered again.
7 Riley
Riley may get a mention in the game as Ellie's first major relationship, but considering that Dina seems to be her girlfriend in the game, it's not likely that Riley will return even through flashbacks. The Last Of Us Part II seems to be focusing very heavily on this relationship with Dina, and if Riley were to return, it could take away from that.
It'd be a neat callback to the DLC from the first game to have her return in some sort of fashion but it wouldn't be a disappointment if she's completely left behind as she's a part of Ellie's past that she may have locked away.
6 Sarah
Considering this story is focusing on Ellie and she didn't really know Sarah at all besides the fact that she was Joel's daughter that passed away, it's very likely that Sarah won't return in any form at all in the sequel. The only plausible way that this could happen is while playing as Joel if there's a section in the game where he's searching for Ellie in a near-death situation. He may get reminded of his daughter but Ellie has kind of taken over that role now, and there wouldn't really be a reason for her to return.
5 Tess
Tess is another character that had a big impact on both Joel and Ellie. She risked her life to protect Ellie and unfortunately got infected while trying to get her to safety. This brought Joel and Ellie closer as they had to deal with Tess's death, and it's possible that some flashbacks could be shown. She isn't a major part of the bigger story so it's also very possible that she won't be mentioned at all. Tess was a really cool character and it would have been awesome to have her actually make it through the story of the first game. Her death did bring Joel and Ellie closer, so there's that.
4 David
As of right now, it is unconfirmed if David will return. It is, however, very possible as he had a huge impact on Ellie's life and she could still be haunted by him as she carries out her mission to get revenge on those that wronged her.
David was really the first person that Ellie felt hate for, and in The Last Of Us, she seemed to be traumatized by what happened to her. He may haunt her through some hallucinations or even nightmares throughout the game.
3 Tommy
Tommy is confirmed to be in The Last Of Us Part II as a supporting character. He'll most likely be trying to guide Ellie in the same way that Joel is and it'll be really cool to see more of him. He wasn't really too developed in the first game besides the conflict between him and Joel. It's possible that there'll be more of that, and perhaps some closure for his character arc with his brother, Joel. It's also possible that things may get more complicated as Joel always seems to see things differently than Tommy.
2 Joel
Joel is, of course, confirmed to be in The Last Of Us Part II, as he was revealed to be following Ellie on her quest for revenge. It'll be interesting to see how much of a part he has to play as the story seems to be heavily focusing on Ellie. It's possible that there could be a section of the game where players take control of Joel, similar to how Ellie was playable during a portion of The Last Of Us. There's a lot of theories going around that he may be dead and that he may just be a hallucination that's haunting Ellie. This is highly unlikely but it's a very cool fan theory that would bring a very dark twist to the sequel.
1 Ellie
Ellie is the main character in The Last Of Us Part II. She'll be on a quest for vengeance after events that unfold involving her partner, Dina. She's a lot more mature and stronger in the sequel as five years have passed and it's now been 25 years since the beginning of the outbreak. She's obviously returning as she's the protagonist of the sequel, but it'll be very interesting to see how much she's changed. The trailers have shown that she is a lot darker than she was as a teenager. Ellie also seems to not be on very good terms with Joel and it's possible she may have learned of the events that unfolded at the end of the first game.