Don't Expect a Major Announcement
The March Black Ops 3 update release date came without a major anouncement to the PS4. We saw a small heads up on Twitter for the PC and Xbox One updates, but there was no massive announcement.
There was a big announcement for the February update since Treyarch switched around how the Call of Duty: Black Ops 3 maps and Zombies DLC delivery took place, but that is already out in the open.
With the potential timing of a second March Black Ops 3 update coming near the end of the month to prepare for new DLC, there will likely be some announcement, but it will not match the fanfare made around the DLC 2 announcement.