Posting a video on her YouTube channel, Arden Cho explains that:
I loved my experience on Teen Wolf. I love the cast and crew. It’s been an amazing almost 3-and-a-half years. But unfortunately it looks like we are wrapped up with Kira’s storyline and she won’t be coming back for season 6.
Teen Wolf is an MTV show loosely based on the 1985 film of the same named which starred Michael J. Fox and has been running since 2011, where Cho has been a cast member since Season 3. I’ll admit that the news surprise me considering where Kira Yukimura’s storyline went through in Season 5 and felt there was still more to explore but Cho is hardly the first cast member to suddenly not return and wish her all the best.