Finnpoe

Stormpilot is the slash ship between Poe Dameron and Finn from the Star Wars franchise.

Canon
Finn and Poe share a strong mutual trust through and from the events taking place both in The Force Awakens and The Last Jedi. The two both have important reliances upon each other, having been working together during their escape (TFA) and in making a plan (TLJ).

They also are shown to care for the others wellbeing– the two share a warm embrace after being separated and believing the other was dead. In TLJ, a happy, relieved Poe excitedly runs to assist a confused Finn after he is seen awoken from his coma.

Fanon
Fans initially received the performances of the two characters as having great onscreen chemistry, despite having a few minutes' worth of scenes. Eventually the two were heavily perceived as a romantic possibility, sparking online debate as to whether or not their relationship was merely a "bromance" or not.

An infamous cause to the uprising of the ship is what many refer to as "the lip bite.undefined" After the two reunite on the Resistance base, Poe notices Finn is sporting the flight jacket that belonged to him, which Finn took from the wreckage of their crashed TIE fighter while looking for him from their escape/rescue. Finn immediately tries to take off and return the jacket, but is prevented by doing so. Poe then tells him the jacket suits him and that he should keep it– followed by a quick lip bite and nudge. This was huge to fans, as lip biting can be seen as being very suggestive in a flirtatious or sexual way.

Behind the Scenes
Oscar Isaac is quite publicly open about the ship, and a lot of possible insight comes from him raising up the hopes of dedicated shippers.
 * In an interview with Ellen DeGeneresundefined alongside John Boyega (Finn) and Daisy Ridley (Rey), Ellen asked if any romance will be seen between the characters, to which Oscar Isaac (Poe Dameron) replied, "I think it's very subtle romance that's happening." Isaac then continued, saying you need to look closely to catch the hints, and that he was playing a "very deep romance" with Poe's character– to which Boyega also replied, saying he was also playing romance. Fans saw that the romance Isaac referred to was between Poe and Finn, since most of Poe's extended scenes involved both of them.