From Halopedia, the Halo wiki
The Shroud is capable of approaching battlefield situations in two distinct modes. When deployed, it can generate a persistent cloaking field around itself that also conceals troops, vehicles, and other ordnance near enough to it. When it isn't making use of this function, it can employ a point defense system that can shoot down enemy projectiles. Despite this, the Shroud has no truly offensive capabilities. The Shroud is notoriously difficult to pilot due to its complicated subsystems that are generally unreliable.
Shrouds were used by the Covenant before the hegemony fell apart in 2552. The Jiralhanae general, Atriox, came into possession of a number of Shrouds in the years following the Covenant's collapse. Extensive tinkering with them by his faction, the Banished, has made these units even more difficult to pilot than usual. Atriox spares no expense in maintaining his stock of these vehicles, as they are very useful for defending and concealing raiding parties. The Banished utilized multiple Shrouds against the crew of the UNSC Spirit of Fire during their battle on Installation 00 in March 2559.
Halo Wars 2
Shrouds can be built by all Banished leaders at a Banished Apex. Unlike the other leaders, Let 'Volir is able to have his Shrouds cloaking range increased and longer lasting once the upgrade has been purchased using a leader point. The advantage of having Shroud is it will provide protection against all units by having projectile deflection, but it can only deflect up to 2 projectiles at a time.
The Shroud is absent from Blitz mode despite appearing in the trailer in the 20 second mark.
List of appearances