I first saw Dead Island 2 in 2014 (I think), back when it was being made by Spec Ops: The Line developer Yager. Since then, it's switched developers to Sumo Digital (which still has a page for it on its website), and not made much of a peep since, save for the occasional reminder that it still exists in some form. Today, we've had another one of those, with THQ Nordic's Lars Wingefors mentioning the game during a financial presentation.
"Dead Island 2 is still being worked on. Stay tuned." And that's it. You'll find the relevant video here (go to the 19:00 point to hear it), although don't try and watch the whole thing unless investor chat doesn't send you to sleep. Secret projects from Volition (surely Saints Row 5?), Coffee Stain Studios, 4A Games and Warhorse are also mentioned on the slide you'll see in the video above, too. That last one is probably Kingdom Come: Deliverance 2, set in 1506, which some believe was teased by the studio's Daniel Vávra back in January (the left photo features a whiteboard that mentions KCD2—1506').
For context, the original Dead Island released in 2011, during the first half of Barack Obama's presidency, and when LMFAO's Party Rock Anthem was tearing up the charts. That was a long time ago. Since then, we've had a standalone expansion in Riptide, and several unnecessary spin-offs, including a long-shuttered MOBA. Original developers Techland went off to make Dying Light, a very solid freerunning zombie FPS that's getting a better-looking sequel at some point soon.