The New Mutants

The vision Dani sees of mutant children contains some reused footage from Logan (2017).

Characters are kept at the facility behind a force field so they cannot escape. Illyana's mutant power is teleportation. She has to go to Limbo first, then she can teleport anywhere/when she wants. She is shown teleporting during the battle. So her powers aren't blocked. She could leave the facility at any time, and she would be able to teleport others with her.

In a deleted scene, Illyana talks to Bobby, where it is established that she is incapable of teleporting out of the force field.

The opening title and closing credits are accompanied by snowfall.

Edited from Logan (2017)