The Bombardment Strike is now available in Warzone as a kill streak to purchase with a key from the new Containment Monitor Stations. Bruno has created a guide to understand this streak and how to use it in Warzone.
First you find the containment monitor station in the zombies outbreak area. At the time of the writing this is still the bank in downtown, but should be moving to the TV station soon. This guide should work in further containment areas as well as they change areas of Verdansk. Activate the zombies, then eliminate 40 of them. Get the yellow access key card from the last zombie and then use it on the loot box. There is a new purple access key card called the Protocol Access Key, or Containment Monitor Item that will appear in the loot. Trade this purple key card to the containment station to start the bombardment strike. The strike will occur automatically in the area around the start of the strike. A black circle will appear on the mini map through out the duration. The bombardment strike lasts 69 seconds.