Certificate Revocation with intermediate CAs – combine CRLs?

I use Nginx for client-side-authentification. Only the SSL-certificates from the User CA should have access to the application. The CA hierachy:

Root CA     | Intermediate CA     | User CA 

So ssl_verify_depth (maximum verification depth) =3

Each CA has a crl.

For Nginx I need one crl-document.

Do I need to combine the CRLs of Root CA, Intermediate CA and User CA?

Thank you very much. Unfortunately I couldn’t find any related questions, (and I apologize if this is a stupid beginner’s question.)