As of Generation 9, the move that cannot be blocked whatsoever, regardless of circumstances (except, as Amethyst said, Max Guard), is:
Hyperspace Fury
I am using this list as a reference, but I cut out pretty much all of the moves. Basically, all attacking moves, such as Future Sight, Doom Desire, Feint, either have a type that's immune to it or have 100% accuracy, and that matters because a Pokémon that can boost Evasion can theoretically dodge them. Following that, all status moves are blocked by Good as Gold. As such, Hyperspace Fury is the only move that can land with 100% guarantee in any circumstance.
Additionally, Urshifu using Aerial Ace checks all the boxes: no types are immune to it, and Urshifu's Unseen Fist is able to ignore Protect.
It is worthy to note that the invulnerable turn of moves like Dig and Phantom Force cannot be dodged, with the only exception being Toxic used by a Poison-type, which obviously is blocked by Protect.
Hope this helped!