After April Security Patch, the Verizon-based Pixel 4 and 4 XL are receiving a second update that enables eSIM on both the devices. This will make the smartphones support two SIMs at the same time.
During the launch, Pixel 4 and 4 XL came with single SIM support, but Google didn’t release any info about the eSIM support. Electronic SIM or eSIM is embedded into the motherboard. These are then used by various carriers to program the contact number and details into the SIM. That too without using those Nano SIMs. However, considering that Pixel 4 already supports those physical nano-SIM cards, a second SIM acceptable.
Now with the new eSIM support, you can get Dual Standby, or receive calls from the second SIM. However, you cannot use data services on eSIM, if the physical SIM is using the same. But in most cases, that is an obvious thing.
Verizon has included all the system enhancements and security updates in this update.
If you want to get the eSIM support, the carrier will tell you how to enable the same.
Source: Android Authority