Bobby Kotick, CEO of Activision Blizzard, speaks at Allen&Co’s annual conference in Sun Valley, Idaho.

David A. Grogan | CNBC

A group of about 600 software testers in Activision on Friday formed the largest union in the US video game industry to date.

The Union was the first to organize under a new employment contract agreed upon as part of of Microsoft Acquisition of Activision for $69 billion in October, the company’s largest takeover to date.

The agreement requires Microsoft to remain neutral with respect to employees who are interested in unionizing and to provide adequate lines of communication and information to resolve these workers. That labor neutrality agreement went into effect after the Microsoft-Activision deal closed in October after months of regulatory backlash.

“We have maintained our commitment to remain neutral during the organizing campaign and subsequent vote,” Microsoft attorney Amy Panoni said in a statement.

In January, Microsoft laid off 1,900 employees in its gaming division.

Activision Quality Assurance United-CWA, the name of the union, is seeking higher wages and more career opportunities, QA tester Cara Fannon said in a statement.

Employees who work for Activision’s quality assurance division in California, Texas and Minnesota have joined the Communications Workers of America to form their union of record.

“Microsoft continues to honor its commitment to let workers decide for themselves whether they want a union,” CWA President Claude Cummings Jr. said in a statement.

Labor organizing in the tech industry has proliferated over the years as large tech firms have grown and come under greater scrutiny for worker protections.

QA workers at Activision, who check games for issues and bugs, particularly emphasized the need for labor protection, noting that their roles felt undervalued compared to software engineers or developers.

Before the deal between Microsoft and Activision closed, QA workers at the video game maker’s Albany branch had also formed a union.

“QA is currently an undervalued discipline in the games and software industry,” Albany wrote social media at this time. “We strive to foster a work environment where we are respected and compensated for our essential role in the development process.”