User blog comment:M3/When will Serena return?/@comment-4990633-20180529100027

There's no clues on when she'll return however if youve watched the movie I Choose You you can see she made a camo appearance in the credits ending so yeah knowing she made a camo appearance i'm alright with that.''

 Plus in one of the Sun & Moon episodes Getting the Band back Together May and several other characters also made a appearance so you know & yeah maybe i have no clue when butt i'll just say maybe Serena will make a camo appearance i have no clue if she'll make a appearance in Sun & Moon alright.

So you know on that hope it helps ^_^..