Sword and Poker (both the original and it's sequel) managed to pull off a successful fusion of RPG dungeon exploration and a deeply tactical variation of poker that kick started the cross-pollination of the two genres on mobile, but for my money POKER KNIGHT from Instant Games takes the concept to near-perfection.
The games battle system hinges on pulling poker hands from two decks but really shines when powers for both the player and opposing monsters are introduced. These show ways to 'cheat' the basic system that wouldn't work in any other environment. The concept that the hand you play and the cards left behind afterward affect damage each turn makes gameplay feel genuinely unique.
I've written a review of the game for My Boxed Universe for those who want to know more at: https://myboxeduniverse.wordpress.com/2 ... er-knight/
and highly recommend anyone with a passing interest in card to RPG hybrids check it out.