I've got question about Slanesh's domiantion playing on response to oponent tactic card.

When oponent play tactic (f.e. Pilgrimage) then i play Slanesh's Domination. And now - is Pilgrimage still on oponent hand (so i can :hit" them form SD) or it "in play" and it's out of range of SD ?

Correct me if I'm wrong, but isn't SD limited to your turn only?

it´s during your turn and

it´s out of range of Sd, because one time the tactic is payed, the tactic is in play and so no more in the hand of his controller.

As was said, Slaanesh's Domination is your turn only, and while yes it can be played in response to a tactic being played, that tactic has already been play, its effect is part of the action chain and the card itself should be in the discard pile (though it is common practice to lay tactic cards on the table while its effect resolves they are never considered in play).