The D 23 look at the Rise of Skywalker began with the binary sunset.
Which is very significant in the Star Wars films.
The twin suns represent the Force keeping tally of the balance in the galaxy between the Light Side and the Dark Side.
Behind Rey and Kylo/ Ben are the binary suns, which I believe represents that they are the balance.
Rey's side of the picture is blue representing the Light Side. Kylo/ Ben's side of the picture is red representing the Dark Side.
But despite the the fact that Kylo/ Ben is on the Dark Side, it's actually pretty bright. There is some red, but there's actually a lot of yellow which isn't really a Dark Side color. If you look at some of his promotional photos from the Force Awakens and the Last Jedi, they're usually very dark
Mostly black backgrounds, without mostly only the red light from his saber.
Even in the Force Awakens poster, his part of the picture is way darker than the area where we see the other characters.
However in this poster his part of the picture is way brighter than normal. And it actually looks a lot like some of the promo pictures of Rey from the Force Awakens
The sun is almost the same color and positioned behind them in the same way.
To me there's a lot of hidden symbols in the Rise of Skywalker promos that Ben will be redeemed, the fact that we see him standing closer to the Light Side in a lot of pictures.
This is some fan art I made of Rey and Ben, with the binary sunset behind them.