While we know that HBO and Warner Bros. are pushing very aggressively to make a Harry Potter TV series, ever since the mainline film series concluded one of the primary ways that Warner Bros. in particular has looked to expand the theatrical realm of the Wizarding World was in the Fantastic Beasts franchise.
The franchise was met with generally middling critical reception and middling ticket sales too, and faced its own slate of turbulence and controversy, be it Johnny Depp having to abdicate the role of Grindelwald or the ever-present arguments surrounding creator J.K. Rowling and her views on transgender individuals. While Warner Bros. decided that these issues shouldn't prevent a second film in the franchise from being made, with Secrets of Dumbledore in the wild for a while now and no signs of a third film anywhere, a leading star has now spoken about the franchise and stated that he doesn't think we'll see any more of it.
In an interview with ComicBook.com, Eddie Redmayne, known for playing the leading role of Newt Scamander in the series, has stated that he doesn't expect to return to the role.
"I think they probably have [seen the last of Newt]. That was a very frank answer, but yeah. And that's as far as I know. I mean, you'd have to speak to the people at Warner Bros. and J.K Rowling, but as far as I know, that's it. I think he may come back in a glimpse in the Universal world in Florida that they're opening up, in which you may catch a glimpse of what he was up to in Paris."
This answer affirms one thing, Redmayne has not been approached about a third film yet, which means even if that was to change in the immediate future, with contract discussions, scheduling, filming, likely reshoots, editing, and everything that goes into making a film from square one, we won't be returning to the Fantastic Beasts series for a few years, and if anything, we probably won't ever again.