For research, breakthroughs and inspirations are made to increase the speed that researchers work at, sometimes instantly being able to complete a project. Other new features include a revamped strategic layer and the 'Bond' system, in which pairs of soldiers develop special abilities that are accessible when both are deployed during a mission, however, when a bonded soldier is killed, their partner may temporarily enter a 'berserk mode', ignoring any player orders and attacking targets at random, or they may panic, becoming uncontrollable and fleeing from battle. Each faction also provides covert ops missions in which soldiers can be deployed to obtain extra resources, delay the Avatar project, or gather info about the Chosen's strongholds, as well as other benefits. The game also introduces three rebel factions that antagonize each other, but grant special hero classes once their allegiance is earned the Reapers, specialized in sniping and stealth, the Templars, who employ unique psionic abilities, and the Skirmishers, former ADVENT soldiers with exclusive equipment and tactics. The Chosen continue to appear occasionally during missions even after being defeated, and can only be killed for good once their base is destroyed as well.

As the game progresses, the Chosen gain new exclusive abilities over time, and eventually become able to launch a direct attack on the Avenger. The expansion introduces a new set of enemy aliens called the Chosen, three elite alien-human hybrid warriors tasked by the Elders to defeat XCOM and recapture the Commander The Assassin, who relies on stealth and melee attacks the Hunter, that uses a long range rifle that fires bullets that track their targets and the Warlock, who uses psionic powers and can take control of several of the player's units at once. The War of the Chosen expansion makes changes to XCOM 2 's campaign structure and adds new enemies, story elements, new hero characters, modifiers, and more behaviors for characters.

A defense team known as XCOM must repel and resist an alien invasion. XCOM 2 is a turn-based tactics video game.

Xcom 2 base layout