It looks like Call of Duty: Modern Warfare's fourth season is set to start on next Tuesday, June 9 2020. Originally, Season 4 was set to arrive on June 3 but was delayed due to ongoing protests in the US.
Call of Duty: Modern Warfare's fourth season was initially scheduled to arrive earlier this week but Activision decided to postpone the launch due to the ongoing protests in the United States. In their statement, Activision wrote that they are moving Call of Duty: Mobile and Call of Duty: Modern Warfare to later dates but did not specifically mentioned new release date for Season 4.
However, it looks like the release date has been found in the game files. According to Modern Warzone over at Twitter, the date that has been found directly in the files and has been verified by their sources.
As you can see, Call of Duty: Modern Warfare Season 4 is set to begin on Tuesday, June 9 2020, 11 PM PST / 8 PM CET. Activision are yet to officially confirm the release date for the new season so you should take this with a grain of salt, even though Modern Warzone is a pretty solid source for Call of Duty info.
Call of Duty: Modern Warfare Season 4 is rumoured to be bringing major changes to the Warzone map, which is set for its first makeover since launch. Leaks and data-mined files suggest that the dam could be going down, resulting in a massive flood all over the map.