There are 2 ways that I know of. One is called a "micro cell". This is provided by your carrier. It provides some cell reception, and then connects to your router via Ethernet to communicate back to the mother ship.
The second option is in essence a repeater. You locate a outdoor directional antenna that "points" to a cell tower. Then inside your house there are omni directional transceivers that connect to your phone, "repeating" the signal to the tower.
These are 2 suppliers that come to mind.
https://www.wilsonamplifiers.com/home
https://www.surecall.com/
Those wilson ones better work. I've tried cheaper ones and didn't have much reliability.