Can iPhone USB Hotspot be shared through a MacBook Pro?
This is possible using System Preferences > Sharing > Internet Sharing.

Cell Network > iPhone > USB > MacBook Pro > Wi-Fi > other devices

In fact, you have to do it this way as the Wi-Fi on your MBP can either join or create a Wi-Fi network, it cannot do both at the same time.

Also, you should check usage terms of your mobile data provider to see if they allow sharing of personal hotspot in this way - some do not.