The Queen of Hearts (QoH) is a minion maker, and her Playing Card Minion gives her a special ability: Taunt.
In its simplest application, Taunt prevents any allies of the Queen of Hearts from being targeted by special skills until any and all Player Card Minions are killed.
As this effect is the result of the Player Card Minion, it cannot be dispelled.
That part is fairly easy to understand.
But if you play the Wonderland Challenge Event, or have or encounter the Queen of Hearts hero, you may wonder:
What happens when I target the Queen of Hearts with a special skill that affects the target as well as the nearby enemies? Are the nearby enemies still hit?
Or you might similarly wonder:
What happens if I use an AoE (area of effect) skill that doesn’t target any particular enemy, and instead affects all enemies? Do they work as usual?
Additionally, it’s worth noting explicitly:
A dispeller like Sonya, Caedmon, Sabina or Melendor can only affect the Queen of Hearts when Taunt is active, just like any other special skill
Taunt is a function of the Queen having at least one Playing Card Minion, and cannot be dispelled — but can be stopped by killing her Minion(s)
The Queen’s defense against special skills can be dispelled
And Here We Can See This In Action
Image: Queen of Hearts with an active Playing Card Minion
Image: Queen of Hearts with multiple status effects applied to her by special skills. Note that the other bosses were unaffected due to Taunt.
And in conclusion about these screenshots: