AT&T, T-Mobile and Verizon reportedly won't support eSIM until late 2018
https://www.cnet.com/news/at-t-t-mobile-and-verizon-reportedly-wont-support-esim-until-late-2018/
This allows iPhone users to switch between two numbers on the same device.
However, AT&T, T-Mobile and Verizon all won't support eSIM immediately, according to MacRumors, which highlighted technical issues the feature creates.