Bungie officially cancelled the Iron Banner event in Destiny earlier this week, following an issue that prevented players from joining the event. The issue that caused the cancellation was the very same issue that plagued Trials of Osiris previously.
At the time, Bungie cancelled Trials of Osiris until they could fix the bug. Unfortunately, the bug moved on bringing the cancellation of this week's Iron Banner. Some Destiny players still had hope that the Iron Banner would make a return sometime this week – it will not.
.@M8J8W We need to fix an issue with Iron Banner before it can return. At this point, we don't plan to start it mid-week for a short run.
— Bungie (@Bungie) June 22, 2016
Bungie does not want to bring the Iron Banner back in the middle of the week and give players a limited amount of time with the event. The develoeprs may bring the event back next week, however there is not official ETA on when the Iron Banner will return.