How can make a zombie follow me withoutnit going through the terrain or any other colliders ?
for this kind of searching, you will most likely need to look into a pathfinding sollution, which will involve the creation of some form of navigation structure like a navmesh or waypoint connectivity graph, then look at searching for paths, maybe combine in some ray-casting to check for visibility through / over walls etc.
hope this helps point you in the right direction.