Tessellation doesn't work

Hello everyone,
Please help me to solve this problem!
I made a material but the tessellation doesn’t work.
The edge still looks smooth and no bump.
I’ve watched a lot of tutorials and and tried the exact same thing other people did, it worked for them perfectly but I don’t see any displacement on my material and don’t see tessellation in wireframe mode either…
Here’s a screenshot of m setup:

Can anyone please help me?
I really want to know what’s wrong with my setup…
Thanks in advance!