Going into the Pro Tour, Standard was an incredibly narrow format. Red midrange decks were still tier one, though there were some rumblings that the archetype was no longer was it used to be. Green aggro decks received some new tools in the form of Thorn Lieutenant and Vine Mare, and Grixis Midrange with Nicol Bolas, the Ravager had been popular at recent SCG Tour® stops.
What there wasn't a lot? Control decks. Despite the power of Teferi, control was not popular going into the Pro Tour, and it's in those metagames that you can get wacky.
And get wacky some players did.
When most people think of beating creature decks, sweepers, and efficient removal is the first thing to come to mind, but aggro and midrange decks these days have too wide a range of threats for that to work consistently, so the better answer is to play a game where you can effectively ignore creatures.
Fog effects like Haze of Pollen and Root Snare do exactly that, and both conveniently cost two-mana, letting you cast them off the lands you untap with Teferi, Hero of Dominaria. Every fog is effectively a Time Walk against most of the Standard metagame, letting you accrue card advantage via planeswalkers and Search for Azcanta.
But eventually you do have to win the game. And you can certainly run out of fog effects. That's where Nexus of Fate comes in. The Time Walk lets you continue to gain card advantage from planeswalkers, but the real kicker is the fact that Nexus of Fate shuffles back into your library afterward.
With no space used on removal, this deck has lots of velocity, so after several turns of fogging and time walking, your library gets quite small. Eventually it becomes academic to find a Nexus of Fate every turn, ultimate Teferi, exile all your opponent's permanents, and win the game with some Karn-structs. It may take a while, much like decking your opponent while repeatedly -3ing Teferi on itself, but you don't want any air in your deck and blanking all opposing removal is important.
The deck is so well-suited towards beating creature decks that your entire sideboard is devoted to control and Aetherflux Reservoir combo decks. While it didn't break into the top 4, this was the breakout Standard deck from the Pro Tour, and you better have a plan for beating it for the next few months until Ravnica Allegiance is released.