WWE Backlash (2019)

Although WWE had never formally announced Backlash 2019, a trail of evidence, including the company's touring schedule and listings for the Pechanga Arena in San Diego, more or less unofficially confirmed it.

Why It Was Cancelled

 * 1) The cancellation reasons are unknown.
 * 2) Now, it appears to be unofficially unconfirmed.

Result

 * plan was kept, but the Backlash 2019 was permanently cancelled.
 * The scheduled 2019 event was canceled and replaced by Stomping Grounds

Source
https://uproxx.com/prowrestling/wwe-backlash-2019-canceled-saudi-arabia-show/