In the Elden Ring Shadow of the Erdtree DLC (Review) much of the focus is on Miquella the Kind, so you'll come across his cross throughout your journey. The sign of the cross indicates places where Miquella has been and is a trace of tracking the missing individual. If you want to track them down, here is the location of all Miquella's Crosses in Elden Ring Shadow of the Erdtree.
Elden ring Shadow of the erdtree walkthrough – All 13 miquella cross locations
Outside of story implications, Miquella's Cross also has items like Scadutree Blessings in front of it.
The first Miquella's Cross in the game appears in front of the Three-Cross Site of Grace. This is where you will meet three Elden Ring Shadow of the Erdtree NPCs – Leda, Redmane Freyja and Hornsent. This is also where Hornsent tasks you with finding the remaining two Miquella's Crosses in the game, the first of the remaining ones.
Before entering Belurat Tower's ancient dungeon in the Elden Ring Shadow of the Erdtree, you will find a Site of Grace at the Main Gate Cross. Next Miquella's cross is in front of this place of grace.