How can I backup my iCloud data with my cellular data

That is only an option in limited circumstances. See the following from Back up iPhone - Apple Support

Note: On models that support 5G, your carrier may give you the option to back up iPhone using your cellular network. Go to Settings > [your name] > iCloud > iCloud Backup, then turn on or off Backup Over Cellular.

Can it be done

Yes, as FoxFifth posted, if using a 5G Apple device on a 5G network that supports that. Otherwise, no.