Poe Dameron debuted another new X-wing starfighter in Star Wars: The Rise of Skywalker, and its color scheme was seemingly a tribute to BB-8. Introduced early in Star Wars: The Force Awakens, Poe and BB-8 have a strong bond that pre-dates the movies, and it's shown how they're close companions throughout Disney's sequel trilogy, even if they're often separated on different adventures. Poe is clearly shown to have a great affection for the astromech droid, and that might've made its way into the latest version of his ship.
Poe doesn't have a great deal of luck when it comes to his X-wings. In The Force Awakens, Poe uses an X-wing that is destroyed on Jakku, following the arrival of Kylo Ren and the First Order on the planet. After that, Poe goes back to using what had been his preferred X-wing - called Black One - which was a black and orange variant. This, however, was also destroyed following on attack on the Resistance base in Star Wars: The Last Jedi. That meant he needed another new X-wing for The Rise of Skywalker.
Although the same model as Black One - a T-70 X-wing starfighter - Poe's new X-wing differed in one obvious way, with the color scheme switching out the black for a lighter grey, almost white design to complement the orange. Of course, that color scheme is very familiar, because it's also the exact same one used on BB-8, who has both white and grey panels alongside the orange accents. Although it's unconfirmed that Poe deliberately had his new X-wing designed after his astromech companion, it does seem pretty likely given how close the two are, and just how much the ship matches the droid (h/t u/thecircularblue on Reddit).
While it's nice that Poe would want to honor BB-8 with the design of his X-wing - and in fitting with the loyalty displayed by the pair to one another - there may be another reason for it. BB-8 was very close to being destroyed both times Poe's X-wings were - he was there for each, and as with Poe himself he narrowly avoided disaster. Because of that, Poe might feel a sense of superstition or that BB-8 could bring some luck when it comes to surviving, since he keeps on doing it, and so that would give him an added reason to use the new color scheme rather than go back to black.
The only problem with this is that BB-8 doesn't get to fly with Poe in Star Wars: The Rise of Skywalker. BB-8 is part of the ground assault team in the film's final battle, accompanying the likes of Finn and Jannah into battle. In his place, R2-D2 accompanies Poe in his X-wing, seemingly to give the droid something meaningful to do, since the sequels had largely ignored him. It would've arguably made more sense for BB-8 to fly with Poe on one last mission to defeat the First Order, but at least the color scheme means he was with him in spirit.