Warbond focuses on shifting from open combat encounters to a more covert and tactical style of play. However, on the eve of the launch, Arrowhead Game Studios announced that they had discovered a critical issue during final testing that did not meet their quality standards. As a result, the release has been postponed without a new date being given.

"During the final testing of Warbond, we discovered a key issue that did not meet our standards for release... We will take a little more time to fix it... I appreciate your patience," the studio said in a statement. [Reddit]
The following items will also be added with the update:

The exact release date is still unknown.