This is just speculation of course, and with fans never being given a release date to begin with, it’s possible the series (which will revisit the Discovery team following their voyage 1000 years into the future) may have been planned to be held for Fall 2020 or early 2021.
Star Trek: Discovery’s release may be delayed, though it is worth noting it hasn’t been given a premiere date to begin with.
Executive producer Heather Kadin told TrekCore.com production was estimated to be complete by May before the pandemic, so it’s possible the delay means the show won’t be finished in time for a summer release.