In XCOM 2, there are a few ways to recruit new soldiers:
- Guerrilla Tactics School: By building the Guerrilla Tactics School facility in your Avenger, you can unlock the Squad Size upgrades, which will allow you to bring more soldiers on missions. Additionally, once the Guerrilla Tactics School is built, you can purchase the "New Guy" upgrade, which will give you a new rookie soldier.
- Resistance Headquarters: As you gain influence with the various resistance factions on the strategic map, you may receive offers to recruit soldiers from those factions. These soldiers will be randomly generated and will vary in their abilities and starting rank.
- Rescue Missions: Occasionally, you may come across a mission where you are tasked with rescuing a civilian or VIP. These missions may also have an option to extract a new soldier, who will be a resistance fighter that has been captured by the aliens.
- Recruitment via the Black Market: In the Black Market, you may have the opportunity to purchase soldiers for a fee. These soldiers will also be randomly generated and will vary in their abilities and starting rank.
- DLC-Specific Methods: Certain DLCs like War of the Chosen and Chimera Squad have unique mechanics that allow you to recruit soldiers in different ways such as Faction Heroes, the Progeny or Spec-Ops units.
Keep in mind that recruiting new soldiers will cost supplies and/or intel, so make sure to budget accordingly. Additionally, soldiers that are recruited may have different abilities and stats depending on their class, so it's important to consider your team composition and strategy when recruiting new soldiers.