The movie you're likely thinking of is Dunkirk (2017), directed by Christopher Nolan. It features a cast including:
* Fionn Whitehead as Tommy
* Mark Rylance as Mr. Dawson
* Tom Hardy as Farrier
* Cillian Murphy as Shivering Soldier
* Kenneth Branagh as Commander Bolton
* Harry Styles as Alex
* Aneurin Barnard as Gibson
* Jack Lowden as Collins
There is also a 1958 movie titled Dunkirk, which features actors like John Mills, Richard Attenborough, Bernard Lee, and Anthony Steel.
If you're looking for information about a different film, please provide more details, such as the year of release or a more specific title.