Polearm Master allows a PC to make an opportunity attack when an enemy enters within reach.

With the Brace manoeuvre, you can use a reaction to make an attack, expending a superiority die.

> 
> **BRACE** When a creature you can see moves into the reach you have with
> the melee weapon you're wielding, you can use your reaction to expend
> one superiority die and make one attack against the creature, using
> that weapon. If the attack hits, add the superiority die to the
> weapon's damage roll. *Tasha’s Cauldron p.42*
> 
> 
> 

Do these features stack, meaning - can they occur simultaneously or on the same turn?
What would be a way to make use of both of these character abilities?