As an organiser of the LANsilesia (basically the Polish LAN) I can confirm it is going to happen in 2020.
Winter edition may be in February 7-9 in Hackerspace Silesia (Katowice) and the summer edition is going to be between 16-July 16-19.
Since we had like 45 attendants last summer we are looking for a bigger venue, so we will be able to cover 60+ gamers.
Also we are looking for a sponsor(s).
Previous editions can be seen at https://lansilesia.tf