"The Originals" Season 4 is all set to premiere next week and it looks like Caroline would be shifting from the Mystic Falls to New Orleans. This is because the recently-concluded "The Vampire Diaries" Season 8 finale showed Caroline receiving a letter from Klaus and it is being said that it could be an indication of her possible crossover.
"The Originals" Season 4 might see Caroline making an entry to New Orleans. According to TVLine, Klaus' letter to Caroline was the biggest gasp-worthy moment from "The Vampire Diaries" Season 8 finale and it could be a hint that she might be crossing over to The CW series. Even TVD executive producer Julie Plec agrees that there are more stories to be told and that "The Originals" Season 4 has the opportunity to visit with some of these characters.
She also said that there are future shows down the line that can be built out of the world of "The Vampire Diaries". However, it is a hope for the future if nothing else. When asked about the crossover of Alaric to "The Originals" Season 4, she revealed that his appearance would be more in line with the timeline of that last scene with the letter. She also said that Caroline would be alive and kicking for many centuries to come.
Meanwhile, there are several characters from "The Vampire Diaries" that are considered to be perfect transplants to "The Originals" Season 4. According to Screener TV, Caroline tops this list and the letter from Klaus is a promise that she would find her way back into his arms. Now that she runs a school for magical children, the setting is perfect for her to make the move.
Another name is Tyler and his epic feud with Klaus makes him a fine crossover option. Katherine too seems like a good fit to move into "The Originals" Season 4. Last but not the least, Alaric too seems like an ideal fit. Since he has already made a move, it would be a good idea for him to settle in New Orleans forever.