The iAd App Network will be discontinued as of June 30, 2016. Although we are no longer accepting new apps into the network, advertising campaigns may continue to run and you can still earn advertising revenue until June 30. If you’d like to continue promoting your apps through iAd until then, you can create a campaign using iAd Workbench.
This, however, doesn't mean that Apple is discontinuing iAd completely. Benjamin Mayo explains:
The announcement is confusingly worded, but it does not mean that all of iAd is being discontinued. Developers will still be able to show iAd banners in their application; it’s just that the inventory for App Store apps to advertise will no longer exist. This is a blessing and a curse — it won’t help iAd improve its fill-rates but the CPM on these type of ads was significantly lower as the buy-in from the publisher side was also lower.