Bungie announced that Iron Banner is coming very early in July, giving the players barely any breathing room between the two Pinnacle extravaganzas.
Iron Banner is returning to Destiny 2 on the next weekly reset, on Tuesday, June 29, 2021. While it's coming almost back to back with the previous IB, Bungie pointed out an important fact - Grandmasters are going live and players are probably still gearing up for those pinnacle caps in order to not deal less than optimal damage.
With the Pinnacle shower that is Iron Banner, players can put the finishing touches on their gear sets in order to meet the Light level required. Well, Power level, now that we're wielding Darkness to I guess.
Anyway, the Iron Banner drops were previously fixed so if you're fishing for a Riiswalker with a great roll, this might be another chance for you. Alternatively, there are a few other interesting pickups given then deep perk pool for all the featured weapons. Then again, it's a double-edged sword since the larger pool means a lower chance of getting the desired rolls.
Bungie also announced that this Iron Banner will not be the last one of the season since another one is planned in the future. It also remains to be seen how they will handle the longer season cycle due to the Witch Queen delay.