By now, there's a good chance you've already seen the new trailer for Justice League.
There's the usual mixture of explosions, trailerspeak, villain-hinting and the like, but the trailer starts off with a tender moment between Clark Kent / Superman and Lois Lane. There's not much to it; it's just Superman and Lois in a wide corn-field at sunset before it cuts to Lois dropping dirt onto Kent's coffin.
Here's a screenshot of the scene in question.
So, does it look familiar? If you saw Richard Donner's 1978 movie, it should. It's more or less a copy of a scene early in that movie when Clark talks to his mother in the family's cornfield about leaving home to become Superman.
They've even got it down to the red-and-black jacket, too. This isn't the first time that a reference to Richard Donner's Superman was spliced into one of the DCEU. Wonder Woman had a similar scene where Gal Gadot jumps in front of Chris Pine and stops a bullet, so it's a common thread.