'Vladimir' and 'Estragon' are the two characters from -

Waiting for Godot, a tragicomedy in two acts by Irish writer Samuel Beckett, published in 1952.
It was a true innovation in drama and the Theatre of the Absurd’s first theatrical success.

The play consists of conversations between Vladimir and Estragon, who are waiting for the arrival of the mysterious Godot, who continually sends word that he will appear but who never does. They encounter Lucky and Pozzo, they discuss their miseries and their lots in life, they consider hanging themselves, and yet they wait.

Source: Britannica.com