According to Naughty Dog's official Twitter account, the last DLC for The Last of Us entitled the Grounded Bundle will be arriving "the week of May 5 globally." The acclaimed developer suggests that you watch its Twitch stream for additional information.
This likely means that this Grounded Bundle DLC will release on Tuesday, May 6th, in the States and the following day in other territories, but no official date has been confirmed.
For a recap, reported earlier by Alex, the bundle will include both single-player and multiplayer components, including an even higher difficulty level (as if it needs one) where "AI is relentless, smart, and brutal" as well as four maps, five weapons, and various kills spread throughout the Reclaimed Territories, Survivalist, and Professional packs.
As a reminder, the season pass deal will expire in mid-May, so if you want Left Behind, Abandoned Territories, and all these extra goodies, I suggest you only spend $19.99 on the pass instead of purchasing them individually. Whether this DLC will extend to the remastered PS4 version is not clear, but it would behoove them to do so, or be trapped in a broom closet with four clickers to pass the time...