No SIM slot. Seems like Apple is only thinking of the US market. Will not be getting the Duo as I will not be able to browse the web outside my home.
Edit: Rate limited so can't reply to the comments. I live in Spain, can't switch to eSIM. I know that the US has 100% integration of eSIM across all providers but outside the US it's not that great. I use eSIM and SIM a lot, have lots of cards and subscriptions. For my main subscription I can't switch to eSIM (yet).
Don't your country telcos have esims?
Even mainstream operators in my country have those these days, so you can sign up online without getting to a shop.
Why do you think eSIM is a US only thing? Common in Western Europe and Japan and South Korea and Mexico and Canada and Australia and Thailand as well. China and India are the big outliers, but that can change.
Where do you live that eSIM isn't an option?