The main evidence is:

* It's been a very long time since Super Mario Odyssey (released in 2017), making a new 3D Mario increasingly likely.

* Nintendo has said new entries in major franchises are in development, though it hasn't specifically confirmed Mario.

* The Switch 2 launched without a new flagship 3D Mario, which many analysts find notable.

* Multiple industry insiders and reports claim a new mainline Mario is in development, with some suggesting a 2027 release.

That said, there is **no official announcement, trailer, title, or release date**. The evidence is strong enough that most observers expect a new mainline Mario game, but Nintendo hasn't publicly revealed one yet.

(http://www.autoadmit.com/thread.php?thread_id=5876517&forum_id=2thread_id=599411#49960736)