Take-Two has dropped a heavy hint about the release of a new game from one of 2K's "biggest franchises" in Fiscal Year 2019. This mystery game will be leading the post-April 2018 releases for Take-Two, along with the recently delayed Red Dead Redemption 2.
Here's the full quote from Strauss Zelnick, Chairman and CEO of Take-Two during the company's most recent sales report (emphasis by me):
"Looking ahead to fiscal 2019, we expect to deliver both record Net Sales and record net cash provided by operating activities, in excess of $2.5 billion and $700 million, respectively, led by the launches of Rockstar Games’ Red Dead Redemption 2 and a highly anticipated new title from one of 2K’s biggest franchises"
In the past, Zelnick has made it clear that Take-Two has a number of 'permanent' franchises which have been detailed to be Red Dead, Grand Theft Auto, and BioShock. Take-Two has one more 'big' franchise under their umbrella and that's Borderlands.
In 2014, Zelnick revealed that 2K Marin would be "shepherding" the BioShock series from here on out – which puts it in the running to be the mystery title, but there's still the chance of Borderlands 3 being the teased new title. We saw some fairly early builds of Borderlands 3 during GDC 2017 earlier this year.
With Zelnick specifying Fiscal Year 2019, we won't be seeing either Red Dead Redemption 2 or this mystery game release prior to April 1st, 2018.