WARNING: The following article contains spoilers for Sicario: Day of the Soldado, in theaters now.
Fans who enjoyed Denis Villeneuve's Sicario in 2015 were sorely disappointed when it was revealed a sequel was being made without Emily Blunt. Blunt's Kate Macer, an FBI agent, was one of the movie's more engrossing characters, embedded in a special task force led by Matt Graver (Josh Brolin) on behalf of the United States Department of Justice.
Not only was she a complex yet passionate heroine, she proved to be the perfect foil to Benicio del Toro's Alejandro Gillick, the franchise's tortured hitman obsessed with killing the Mexican cartels who murdered his family. What made her so intriguing was she was the moral compass and overall voice of reason of this black-ops squad as they repeatedly broke the rules.
However, Sicario: Day of the Soldado, a clear follow-up, leaves a lot of wiggle room for Blunt to reprise her role in the third chapter, given that the US government doesn't want loose cannons for watchdogs anymore.
Writer Taylor Sheridan revealed after Sicario, he felt her act was complete, which is why she wasn't brought back. There, she was used as a pawn to weed out crime boss Fausto Alarcón for Alejandro to kill and avenge his family, and to help Colombia's Medellín cartel cripple their Mexican counterparts. In the finale, Alejandro forced Kate at gunpoint to sign documents legitimizing the operation, something she ended up doing against her will.
She was left with one opportunity to kill the hitman, which he offered as he nonchalantly walked away, but she didn't take the shot. This confirmed while her conscience was torn, she accepted he was a necessary evil. But Sheridan and producer Trent Luckinbill have both indicated they'd love to have her again, with Blunt also expressing interest in returning if the story wanted her. And given how the war on drugs escalates in Soldado, she'd fit the threequel as the game has changed big time. More so, the Americans need a composed, level-headed individual to fix what Matt and Alejandro broke in this new narrative.
The first way she can reprise her role is by replacing Matt as the head of this special-ops unit. In the franchise, he's a tactician for hire, working with the CIA, FBI and just about anyone the DOJ can offer him to destroy their enemies. Soldado, though, saw him truly cutting loose, even disobeying direct government mandates. As he and Alejandro pit rival cartels against each other, they kidnap Isabela Reyes (Isabela Moner), framing the Matamoro gang for it. When the latter engages the Reyes cartel in war, the mission's more or less accomplished, but Matt's team leaves a lot of clues to blow their cover.
As they try to return Isabela to Mexico, things fall apart and Matt has to flee to America, leaving Alejandro behind with her. Matt's superiors instruct him to go kill them but he instead brings Isabela back into witness protection. This insubordination is sure to have dire consequences as the Mexican cops and gangsters his team executed publicly created a political conflict.
If anything, Kate can rectify the abduction and subsequent return of Isabela, resulting in an interesting mother-daughter dynamic, something Sheridan hints Isabela didn't have. Matt's boss Cynthia Foards (Catherine Keener) was fed up of his hot-headed behavior so Kate could well be the perspective the DOJ requires, especially one they can control.
Secondly, Kate can easily be worked in as someone with the experience necessary to take out Alejandro. Foards already has one loose end in her possession -- Isabela -- who knows about the botched kidnapping, so she can easily manipulate things to get Kate to go after him. With the political tensions high and cartels now officially classified as terrorist organizations, such an enemy of the state is sure to be deemed a terrorist, so a person who has the knowledge of how the Sicario operates would be ideal to lead the manhunt. Alejandro is last seen hiring a gangbanger to train as his successor as he wants to finish the job on the Reyes family, thus a skilled mind like Kate, who can move quickly and think like Alejandro, is the best bet to kill the hitmen.
As we saw in Soldado's predecessor, Kate has the intelligence and compassion to defuse this predicament the Americans are in presently. She's a brilliant strategist and most importantly, she can be used to execute missions by the book. She was written to be Matt's polar opposite, so this alone makes her the perfect G-Man to restore order in the chaos-driven Americas, as she also knows the landscape and players so well.