ZeniMax employees involved in the campaign, which included only quality assurance, or Q.A., workers, said Microsoft’s neutral stance came as a relief. “It was nothing short of an absolute gift,” Autumn Mitchell, a worker active in the union effort, said during an interview last month.

In a further sign that unionization is gaining traction across the gaming industry, workers at a Boston studio owned by Activision announced last week that they had filed a petition to hold a union election.

Two other Activision studios have already voted to unionize — one in Wisconsin and the other near Albany, N.Y. But unlike those studios, the proposed union at the Boston studio, known as Proletariat, includes a variety of workers, such as animators, designers and engineers, not just Q.A. workers. A formal union with broader membership would appear to be a first at a major U.S. game maker.

The Communications Workers of America represents workers at the two Activision studios that have already unionized and would represent the Boston-based workers.

At ZeniMax, which includes the high-profile Bethesda Game Studios, maker of such hits as The Elder Scrolls and Fallout, workers said they hoped a union would improve their pay and hours. Q.A. testers and other workers in the industry have long complained that they must endure grueling stretches of work shortly before a title is released.

Microsoft has said it consults with employees to ensure they don’t take on too much work.

Those seeking to unionize at ZeniMax also said that they hoped to change the company’s approach to promoting workers and to assigning them more responsibility, which they said seemed arbitrary at times, and that they hoped to be able to negotiate more flexible policies on remote work.