The Korean Grand Prix has been removed from the 2020 F1 race calendar, we assume this is for similar reasons to last year. For a short period the race was included in the 2020 calendar, but has since been removed.
There is no official reason released for the race not going to Korea, we can only assume it was because of the political issues in the country at this time. Strangely, the 2020 F1 race calendar still says that they will be running 21 races but only 20 are currently listed, so perhaps we could be getting a surprise new location for the 2020 calendar.
2019 Formula One Calendar Highlights
For a quick look back on the highlights of the 2019 season take a look at the video below.