This is the Netflix film, The Old Guard (2020).
A covert team of immortal mercenaries is suddenly exposed and must now fight to keep their identity a secret just as an unexpected new member is discovered.
![Image of (from left to right) Joe, Booker, Andy, Nicky and Nile, from "The Old Guard" (2020).](https://i.sstatic.net/tRdeJl.jpg)
At the start of the film, we're introduced to Andy, Booker, Joe and Nicky; a group of four immortal warriors from different parts of the world who've been allied with one another for centuries. Andy (played by Charlize Theron) is the leader, the oldest, and the most skilled fighter of the group.
They're not portrayed as witches or explicitly magical in any way. Their only powers seem to be slowed/static ageing and rapid healing. In the present day, they operate as mercenaries taking on rescue missions and such, but they've been trying to do good in the world for as long as they've been together.
Over 500 years earlier, Andy and another female immortal, Quỳnh, were captured in England, accused of witchcraft, and hung. When that didn't kill them, Quỳnh was sealed in an iron maiden and dropped from a ship to the bottom of an ocean. The other immortals never managed to find her and assume she's still trapped there.
Back in the present, a young U.S. Marine named Nile Freeman inexplicably recovers after having her throat slashed during a house search in Afghanistan. When this happens, the other immortals start seeing her in their dreams and vice versa. Apparently, this is how they all found one another to begin with.
Soon after, Andy tracks Nile down, captures her, and takes her to France to meet the other immortals, who're currently using an abandoned, rural church as a hideout. According to Andy, Nile is the first new immortal they've found in 200 years, Booker having been the most recent before that.
The main antagonist of the film is Steven Merrick, the CEO of a pharmaceutical company who wants to capture and run tests on the immortals to find the secret of their powers, so that he can monetise it. He employs his own private army of mercenaries.
It's revealed near the end that Booker sold the other immortals out to Merrick, since he was tired of immortality and hoped that Merrick's scientists could find a way to end his life. He regrets what he did and subsequently helps them, but they decide to expel him from the group for a century as punishment.
In the closing scene, a dejected-looking Booker arrives at his home and finds Quỳnh there waiting for him. While pouring herself a glass of water, she calmly says "It's nice to finally meet you" and then the screen fades to black.
According to Wikipedia, a sequel film is currently in development.