Today I deployed a new CentOS 8.1 machine, yes I’m still doing some Linux, and immediately after installing the OS I ran the update command which did not yield any result
dnf update Dependencies resolved. Nothing to do. Complete!
It turns out this a documented bug affecting even recent build, I generally use the minimal or boot ISOs, builds you can read of it here.
Solution is really simple issue the following command:
dnf install -y centos-release-stream dnf update
This time updates will be correctly downloaded and installed on the system if you choose so.