Newsarama has confirmed that Justice League of America is ending with April's #29. This follows the recent confirmed cancellations of Trinity, Bombshells United, Batgirl and the Birds of Prey, Supergirl and Super Sons. A source close to situation confirmed series writer Steve Orlando's run was ending, as was the volume as a whole, as part of May's weekly Justice League: No Justice weekly miniseries.
No Justice co-writer Scott Snyder previously tweeted that JLA, Teen Titans, Titans would be "rolling into" No Justice but no one involved had said definitively if the titles were on hiatus or were definitelely cancelled. Given the new confirmation of JLA's end, the absence of Teen Titans and Titans from DC's May 2018 solicitations could signal those series' cancellations as well.
(Of course, given superhero comics they could be relaunched with a new #1 down the road...)
Orlando also confirmed Tuesday that his long-running Supergirl series was ending in April as well.
Originally launched in February 2017 as part of a second wave of "Rebirth" titles, JLA recently featured the surprise return of Alan Moore and J.H. Williams 3's Promethea to the DCU proper.