The Control Ward has replaced the Pink Ward in the preseason patch.
The Pink ward revealed invisible items and characters and also granted the player and their team the ability to attack these items / champions. This meant when a pink ward was placed, it would reveal all enemy traps, ward and champions that were previously invisible in a circular radius.
The Control ward allows players to disable enemy wards in the radius that it is controlling. Similar to the Red sweeping trinket, it will disable to enemy wards to prevent the vision previously granted by the enemy’s vision ward. Hidden / invisible traps will also be revealed, such as Teemo mushroom while the Pink ward also does.
The major change in the Control ward however is the lack of ability to reveal invisible enemy champions. Unlike the Pink ward which revealed all invisible enemy units, such as Vayne and Shaco when in stealth, the control ward will be unable to do this.