That really means anyone you find -- the bartender, the security guard, the university worker whose father is in debt or the loan shark preying on him.
They will form a collective of up to 20 characters, after you win them over individually through mini-missions. You can freely switch between members of your squad, who carry different expertises -- think GTA V's mechanic but much much bigger. When not controlled by you, teammates will go about their daily lives at work, home or the pub. Cutscenes will play out differently according to the character who's in them. But mishandle your protagonist and they might be captured, or even suffer permadeath.
The London of Legion, after all, is more V for Vendetta than Bridget Jones. In a post-Brexit future, the UK capital is overrun with private security contractors, drone swarms, resistance fighters and cyberpunk clichés. AI has caused mass unemployment; the shiny cars you can hijack are able to drive themselves. But your characters are hackers, so they can surf giant delivery drones over an enemy base in Camden Town or tap into ever-present CCTV systems for reconnaissance.
The UK's encroaching surveillance culture and messy, protracted divorce from the EU are both volatile current topics that would seem ripe for a statement -- yet Ubisoft seems to have a penchant for teasing hot-button societal issues in its games only to refrain from saying much that's thought-provoking about them (see: Far Cry 5). Based on my 45 minute early demo at E3, Legion ticks all the boxes of adequate open world gameplay: faithful architectural recreations, combat/stealth/hybrid classes of characters, an infiltration of a police HQ.