Despite not being officially greenlit, the Mario movie is still relevant in the mind of Nintendo president Tatsumi Kimishima who spoke about the movie project in an interview with Japanese newspaper Kyoto Shimbun.
When asked about the Mario movie rumors, Kimishima stated that he hopes to come to an an agreement with a partner soon and hopefully announce the film quickly after that. If everything goes according to schedule, Kimishima believes the movie could be out in time for the Tokyo Olympics in 2020.
There have been rumors about an animated Mario movie for years since the Sony email hack back in 2014 revealed correspondence that suggested Nintendo was shopping the idea around to studios. More recently, rumors were abound that Nintendo was in final talks with Illumination, the animation studio behind the Minions and Despicable Me movies.
Based on Kimishima's interview with Kyoto Shimbun, it doesn't look like Nintendo have a partner just yet, though it is possible they have a deal on the table somewhere.
Before his death, former Nintendo president Satoru Iwata had intended to make Nintendo more aggressive in licensing their intellectual property out to other media, listing movies as one possible avenue. Nintendo as a company had been famously guarded about its properties and movies since the 1993 Super Mario Bros. movie starring Bob Hoskins, John Leguizamo, and Dennis Hopper. Which we can't quite blame them for. That movie was an absolute train wreck on so many levels and didn't manage to do the property justice.
That said, branching out into film, tv, or other media is definitely a smart move for the company. Especially with Super Mario Odyssey being the indomitable hit that it is, now is the time for a Mario movie if there ever was one.