Sacred Sword in Pokémon GO has been a datamined fighting-type move since the end of 2018, but we haven't seen it make it into the game. Anytime there is a brand new moved datamined, you can expect it to either be revealed as a Community Day move or as a move for a brand new Pokémon.
The problem is the fans have been voting for Community Day Pokémon and unless they choose a fighting-type Pokémon, we'll have to wait.
Sacred Sword Pokémon GO: Will the Move Ever Appear?
Machop was one of the options and could have received the new Pokémon move. Alas, it wasn't voted for and Abra is the Pokémon for March. So we might not see the move make an introduction until April and beyond. None of the Legendary Pokémon or special events are prioritizing a fighting-type Pokémon, so March is highly unlikely. At this point, the move could be used for the latest generation of Pokémon in Sword and Shield, but Nintendo hasn't revealed when that generation will make it's way into Pokémon GO.
Until then, we'll have to wait until Sacred Sword finally arrives.