[TD-RPG] Ho to make objects transparent when in Camera PoV?

Hello Devs,

i’m working on a TopDown-RPG game. Not yet a Game, just a big World at the moment.

My actual Problem is, that when i move the Camera throu places with Trees they are hiding everything under them.
Any Ideas how i can make Trees (and other thinks blocking the view) like 90% transparent wenn my Camera PoV enters their hitbox? Or hide verything in the Hitbox of my Camera or making it semi transparent in the center of the Camera?

I tried to search for this, but could not find anything helpfull.