WB tweeted a new teaser for Batman: Arkham Origins for an upcoming Story DLC yesterday, which heavily hints at Mr. Freeze appearing in the game. The teaser hearkens back to the Batman: The Animated Series episode "Heart of Ice", which updated Mr. Freeze's origin, and brought the character back to prominence after a lengthy absence in the comics. In the episode, Freeze confronts the man who caused his condition at a presentation ceremony for a "Humanitarian of the Year" award, which is shown in the video game teaser, along with a heart-shaped diamond.
WB Entertainment did not release the cost or release date of the teaser, but I'm sure it'll pop up eventually.