I also had the same issue after I upgraded to Catalina. I installed UR44 tool and USB driver v2.03 on my macbook pro
I followed the steps offered by @hyunsik but I still did not have sound input from my UR44 within Cubase. Thanks to Chris at Steinberg Support, I’m back up and running!
Try this first!
If you have reinstalled drivers and still unable to get sound or record in Cubase, check the following:
Close Cubase
Go to System Preferences… (Apple menu), open the preference pane “Security & Privacy” and make sure the “Privacy” tab is selected.
Click microphone in the list of components on the left.
If CUBASE is unchecked in the list of apps on the right, click to check it!!!
Launch Cubase
Make sure your audio connections and studio is setup correctly
Test audio track (click monitor for that track…) you should now have sound!
This worked for me…