This article contains spoilers for Future State: Batman/Superman #1 by Gene Luen Yang and Ben Oliver.
Even Superman isn't safe in Batman's Gotham City in DC's Future State. The Dark Knight has always considered himself engaged in a fight for Gotham's future, but DC's Future State has revealed it is a battle he is destined to lose.
Gotham City has turned against Batman and his fellow vigilantes, with Mayor Christopher Nakano signing a deal that has allowed a group called the Magistrate to take the city over. Future State: Batman/Superman is set shortly after the Occupation, and Batman senses the growing darkness but has yet to discern the scale of the threat. He appears to have stepped back from the Justice League, focused purely upon Gotham City, desperate to figure out a way to turn the tide. The relationship between Batman and Superman is tenser than ever before.
Future State: Batman/Superman #1 sees the Man of Steel visit Gotham City, and he quickly realizes he's far from welcome. Not that Superman has any reason to be worried about the less than warm reception he receives, because he's confident he is stronger than anything the Magistrate can throw at him. And so he walks through Gotham without any caution, letting the Magistrate know he's there. Unfortunately, Superman's confidence is misplaced, because by the end of the issue he winds up stabbed by Professor Pyg with a Kryptonite scalpel.
The Magistrate object to vigilantes and superheroes alike, and they don't care whether those heroes are anonymous - or whether they've revealed their secret identity to the world. Superman may be a beacon of hope, a symbol of justice, but to the Magistrate, he is nothing more than an opponent. Worse still, he is ill-equipped to survive in the insanity of Gotham City, with Professor Pyg successfully weaponizing him by finding ways to install his super-powers within his rats. The scale of his ambition is truly breathtaking - much to Batman's growing horror. And it's even more chilling to imagine what the Magistrate would do with the Man of Steel.
This isn't the end of the road for Superman, of course; other issues of Future State are set further on in the timeline and prove Clark Kent will survive his experience in Gotham. But the teaser for Future State: Batman/Superman #2 suggests this is the last time Superman and Batman will ever team up, meaning he will never come back to Gotham again. With the Magistrate in charge, that's probably for the best; even Superman isn't safe in the dystopian Hellhole Gotham City has become.