Developer Infinity Ward has announced that they will be extending Call Of Duty Modern Warfare Season 1, which means that Season 2 has effectively been delayed. It was originally scheduled to end on 28 January 2020, but will now be ending on 11 February 2020 instead.
However, there will be more content awaiting players. This includes a host of new items and challenges, such as an in-game Challenge to earn a new Crossbow weapon, new remixed game modes, and new playlists. During the extended duration of Season 1, there will also be 2XP, 2X Weapon XP, and 2X Tier Progression.
While no reason was given for this extended Season 1 in the official blog post, it is likely because the developer needed more time to work on Call Of Duty Modern Warfare Season 2 content.