In which region Serena comes back

Hy guys anyone know in which region Serena comes back to ash journey if anyone knows please reply me back

Episode 78 airs later this week with Episodes 79 and 80 having been announced. Neither of them involve Serena and something tells me that if she's coming back, it won't be until the 2nd season of the Japanese dub or Generation VIII if she comes back at all. Although Misty is an outlier when it comes to returns(she's returned multiple times), most female companion returns took awhile. May took 75 Episodes(74 if you count her brief appearance at the end) while Dawn took 86 Episodes(briefly appeared at end of 85). Iris didn't appear at all, however so Serena, despite her popularity, might suffer the same fate. Based on the past two performers, Serena is likely to return in the 80's if she's to return at all for Alola. Otherwise, she's slated to get the Iris treatment unless they plan to bring her back for Generation VIII(which would be monumental if it were to happen).

TLDR: We have no clue when or if Serena is coming back.

She is never coming back. Iris never returned, so they're done with old Pokegirl appearances (aside from Misty).

She's not coming back.

I highly doubt Serena is coming back. There's no reason for her to. Maybe she'll return if we get an entire season in Kanto while the wait for the generation 8 games come out. Other than that, I highly doubt she'll be coming back.

& Honestly, Misty and Brock's two episode return was obviously only really a thing b/c the anime had reached its 20th anniversary.