A Smoke Grenade is a utility item in XCOM 2.
|“||Provides a defensive boost to any unit within the radius of the smoke, friend or foe.||”|
Smoke cloud remains in effect for three turns; on player`s fourth turn after using the grenade, all terrain previously covered by the cloud will have its original protection values, and the visual effect of the cloud will have been removed. A notable increase in smoke transparency signalises that the cloud is about to dissipate.
Using a Smoke Grenade ends a soldier's turn.
The Smoke Grenade in the game actually didn't provide any Defensive Bonus due to a bug which is fixed in Anarchy's Children patch.