Thanks for the inputs. We understand that Kamailio is a SIP signalling server irrespective of any core. But we have seen a thread in Open5Gs community where they established the call with Kamailio IMS. Below thread is for your reference. 

If you have any inputs on this it is most welcome. We just want to check the feasibility of establishing voice/video call with 5G core.

Your inputs will be appreciated.

Thanks and regards

Pooja Yadav