The tweet itself doesn't confirm this is an event, but given the way events have been teased in the past, it certainly seems likely. Here's what we know so far.
Overwatch News: New Overwatch in-game event seemingly teased
From the looks of it, the new Overwatch event — if that is indeed what this video is teasing — will center around some sort of occurrence within the Overwatch universe itself, rather than a link to a real-world holiday.
The video appears to mimic some kind of newscast or informational computer display, showing text about "file 00382 - King's Row uprising," some kind of Omnic-related event that was "entered into record seven years ago" and is set to be declassified on April 11.
The lower-right portion of the screen also appears to tease a new skin for Tracer, but it's difficult to tell since that particular panel is intentionally obfuscated. The upper-right portion of the screen looks like it may be teasing a new map or some other in-game location — but again, nothing is certain just yet.
Initially, a Blizzard Facebook account published and soon thereafter deleted the teaser, which made it look as though the video was posted early by accident.
When more information becomes available, we'll let you know.
April 3, 2016, 2:05 p.m.: This story has been updated.
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