Employees demand better protections and remote working options.
Activision Blizzard has yet to recognize the union.
Last month, the board of directors urged shareholders to decline the report.
The agreement will go into effect 60 days following Microsoft's acquisition of Activision.
The floundering expo continues to cling to life.
The family previously brought a suit against the company in March.
Current and former employees are frustrated with the company's "golden boy" executives, and also with CEO Satya Nadella for allegedly enabling them.
The Game Workers Alliance will be the first union in the US AAA game development space.
The Destiny 2 maker is the first in the games industry to pledge action following the recent domestic terrorist attack in New York.