I just got my iPhone 15 pro and set it up from my old phone but I have no Cellular service on my new phone

Hello, some providers support eSim quick transfer, others need to be contacted to activate the eSim in a new phone

Find wireless network providers and worldwide service providers that offer eSIM service – Apple Support (UK)

Contact your cellular provider, who can help get your cellular service activated on your new phone.

If you pay in full for a year, Mint Mobile has a v.e.r.y. affordable plan, and its coverage works very well in downtown San Francisco.