Well, you can without any additional infrastructure. Install agents on those VMs to backup the databases and have on-prem accessible (you’d likely need to use a firewall configuration and punch a port through the firewall to the CommServe and Media agent, or use a proxy/network configuration).

Azure → Commvault network gateway (proxy) on port 8403 → CommServe/MA

Consider that moving data out of the cloud costs egress fee’s $$$ - https://azure.microsoft.com/en-au/pricing/details/bandwidth/

Another approach is to backup in cloud and use an auxiliary copy to copy back on-prem. The best way to do that would involve running a Media Agent in the cloud though in most scenarios.