https://www.gamespot.com/articles/destiny-2s-annoying-phalanx-enemies-have-an-awesom/1100-6453160/

One of Destiny 2's most common and annoying foes is an upgraded version of an old enemy: the Cabal Phalanx. These heavily armored brutes hold a gigantic shield in their off-hand, shooting at you with impunity from the other side. On top of that, in Destiny 2 they've gained the ability to massively increase the size of that shield, extending it on both sides to provide cover for their idiot Cabal friends.

Thankfully, there's something else new about Phalanxes in Destiny 2: their weakness.