The New Mutants director said he was inspired by Buffy the Vampire Slayer’s queer representation in the form of Alyson Hannigan’s Willow.
He wanted to make the effort because mainstream movies haven’t quite caught up to the added representation on television which Buffy started to make moves toward years ago.
As Josh Boone also said to EW, he wanted to extend their connection from Marvel Comics and felt a romantic relationship between them was a plausible extension of their characters.