Open world platforming, Mario in realistic settings, unconventional gameplay (Mario being able to take over enemies and inanimate objects), etc.
Just look at how Yooka-Laylee turned out.
Open world platforming was done back in 64/Sunshine. Plus this is the main Mario dev team led by Koizumi, who knows Mario as close as his creator, Miyamoto. This isn't the former Rare devs who haven't developed in a while and with the type budget Mario potentially has.