Can I use a physical SIM card and an eSIM on the same phone?

On most recent phones, yes. “Dual SIM” phones run a physical SIM and an eSIM side by side. That includes iPhone XS and later, Samsung Galaxy S20 and later, and Google Pixel 3 and later.

It’s a handy way to keep another network’s SIM card in while using Olilo on eSIM. Choose which line handles calls and data in your phone’s SIM settings: How do I choose my phone’s default SIM?