DC's Batman event 'The Joker War' is just getting started really, but given comic books are perpetually months ahead of itself in terms of sales cycles, that means it's about time for the publisher to start promoting their next big storyline.
Look for DC to soon begin teasing a storyline called 'Endless Winter' launching in December 2020. And while details are very sparse at the moment, it appears the storyline is likely Justice League related.
From a totally speculative standpoint, there is a DC character that goes by the name Endless Winter, who dates all the way back to 1940's Action Comics #20 but has a recent connection to the Justice League.
Delores Winters was originally an actress who was kidnapped by the villain the Ultra-Humanite, who had his brain surgically transplanted into Winter's body.
In pure comic book fashion, Winter's own brain was preserved by the assistant of the mad scientist who performed the original brain transplant, and that was later transplanted into another body. Over the years Winters evolved into a villain in her own right who became obsessed with cosmetic surgery to remain youthful and went so far as to transplant her brain into her own adult daughter's body to become young again.
In the modern DC era, this obsession with 'endless' youth and beauty eventually led Winters to have the character Icemaiden kidnapped and flayed, to have the heroine's skin fully transplanted on her body. This gave Winters her alabaster appearance and led her to begin calling herself Endless Winter. She would later lose control of her now metahuman skin, causing snow and ice to generate out of her body uncontrollably.
It's then Winters' story begins to dovetail with the Justice League. Her last appearance was 2010's Justice League: Cry for Justice #5 by writer James Robinson with artists Mauro Cascioli and Scott Clark. Manipulated by JLA villain Prometheus, Winters travels to Gotham City and battles Batwoman, but dies in the issue due to Prometheus's schemes, and her corpse is taken to the Justice League Watchtower.
It's possible, though again, completely speculative, Winters' uncontrollable ice and cold powers will re-emerge at a greater scale to threaten the world, perhaps due to the machinations of Prometheus once again.
Look for more details on DC's 'Endless Winter' in the coming weeks.