iPhone 7 cellular data not working after SIM card transfer

The iPhone 7 may may be Carrier Locked Device.

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

To be able to use any SIM across the globe you must have "No SIM Restriction" against Network Provider Lock. Please refer to the pic below.

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

Device Unlocking Policies | Verizon Privacy Policy

Unlock a Phone or Device - AT&T Device Unlock Portal

Unlocking your Sprint device - T-Mobile

FAQs about unlocking your Sprint device

Unlock Your Phone for Spectrum Mobile

Did you already force restart your iPhone after changing the SIM?

Force restart iPhone - Apple Support

If this does not help, contact your carrier, in case something is wrong with your SIM card.