Generally it is a hardware and software but you can get a ZB Pro that can speak to non pro frequencies but it's a all or none can't exist in both realms and it's a different software stack for the ZCL.
So no the ISY ZigBee unit can't talk to ZHA devices 
but there is a integration for the ISY to talk to Hubitat 
but it's currently one way from HE to ISY not from ISY to HE.
