Trails of Cold Steel has had a home on the PS Vita since the release of the first Cold Steel game. But now, the third and final game in the series is skipping it in favor for being PS4-only when it launches in 2017. The game is currently only confirmed for Japanese markets right now but considering the past two games got localized, it would make sense to guess that this game will get localized as well.
Honestly annoyed it is not releasing on Vita but if it leads to a better game experience using the stronger hardware, I can understand somewhat. The official press release XSEED put out can be found on Gematsu.