Somewhat more significantly, the trailer is listed under the title Insidious: The Last Key, suggesting that the franchise’s fourth installment will break away from the traditional Chapter titles and employ a subtitle for the first time.
The trailer for Insidious: Chapter 4 is expected to drop very shortly, having just been officially rated, and may also have a new title to boot.
The Insidious franchise has proved highly lucrative thus far but every movie series has a point of expiry and there’s an argument to be made that Insidious: The Last Key is that very point.
Insidious 3 ended with Elise discovering an entity had begun haunting her personally and this cliffhanger acts as a starting point for the fourth outing.