It can be found in Pokemon Go's Level 5 Raids right now, but it's difficult to know what the best Landorus moveset and counters are.
As always with Raids in the mobile game, you'll first need to beat it as part of a team. To do it quickly, you're going to need to know what Pokemon are best against it.
Best Counters for Pokemon Go Landorus Raid
Landorus' Incarnate Forme is a Ground/Flying-type Pokemon, so is weak to Ice types. What you'll want to do is build a team of strong ice-types like Abomasnow, Darmanitan, and Mamoswine.
They're Pokemon that combine type advantages with high attack and HP stats, making them tough to take out even for a level 5 Raid boss.
Any other high-CP ice-types you have will be good to fill out your squad with. If you've got a Mewtwo with an ice-type charge move too, that could also be useful.
Then, focus your efforts on using ice-type moves in battle against Landorus too. The likes of Powder Snow and Avalanche will be good moves to use frequently.
What the Best Landorus Moveset Is
After winning the Raid, you'll be able to catch Landorus in its Incarnate Forme. Without a weather boost it'll be between 1965 and 2050 CP, and it'll be between 2456 and 2563 CP with the boost.
Then, once you've caught it, you're looking for a Landorus with Rock Throw as its fast move (although the fast move option isn't that important) and either Focus Blast or Rock Slide as the charged move.
With the best moveset, Landorus will be very strong against Flying, Bug, and Ice types. Yes, it's weak to Ice-type, but it'll be able to cause some damage too.
If anything changes in Pokemon Go and the best Landorus moveset and counters change, we'll be sure to update this guide.