After getting the map from the bandit camp, you'll want to follow the river back up north, which is probably the direction you came from if you're following the quest line to find Mutt.You'll ...

The location of Canker's camp marked on the map in Kingdom Come Deliverance 2. Warhorse Studios. As Gules tells you, Canker has a camp somewhere in the middle of the forest east of Semine.