With rumors floating around a while back about the next batman game after Arkham Knight released in June 2016, but many believed that it wasn’t going to come as Rocksteady announced that this was the last in the series. It seems that might not be the case with the latest possible leak from a user on Neogaf.
On a post from September, a user vetted by the moderators stated

“Indeed, WB Montreal is working on two games right now.
Suicide Squad, in which they go help from Rocksteady.
– is a brawler
– you create your own avatar, grow it out, with tiers of rewards
– many characters to choose
– coop-action
– Borderlands esque
targeted for 2017 release.
Next game is the Damian Wayne game.
– has been greenlit last summer
– 10 years in the future (I think our future from 10 years now, not quite Batman Beyond)
– Bruce is old and has a beard
– harness on his leg
– uses a walking stick
– is mentoring Damian Wayne to be the new Batman
– Damian has a Batbike
– lots of great characters and also new ones, lot’s or redesigns, like Black Mask being a female
– Dick’s in it, has a shaved head
– some other villains are Flamingo, Poison Ivy and White Rabbit(old, looks like a granny)
Game is starting to roll in production, so we might no see it for a while, but I am very excited.”

And following with an edit to the thread that both games will not fall under the Arkham name.
With the first game being a Suicide Squad game does make sense to the ending of Arkham Origins if this is going to be developed by WB Montreal. With Slade Wilson being confronted by Amanda Waller with confidential files to work for her.

And the second game with Damien Wayne leaves me more skeptical. Would WB Montreal be able to pull a game off at that stature? With many believing Arkham Origins was lacking compared to Arkham City with very similar gadgets and mechanics. And many not a fan of the multiplayer implemented into the game by Splash Damage (who worked on Brinks as well). With barely anything on either title, we can only hope something will be announced, possible at this year’s Game Awards in December or even at the Playstation Experience.
Source: http://www.neogaf.com/forum/showthread.php?p=216101370