Mere months after being installed in the job, Kevin Mayer has stepped down as CEO of TikTok.

"In recent weeks, as the political environment has sharply changed, I have done significant reflection on what the corporate structural changes will require, and what it means for the global role I signed up for," Mayer said in a memo to employees.

"Against this backdrop, and as we expect to reach a resolution very soon, it is with a heavy heart that I wanted to let you all know that I have decided to leave the company."

The former Disney exec's exit comes as TikTok, which is owned by Chinese firm ByteDance, is under ongoing fire from the Trump administration, which has demanded it be sold to a U.S. company within 90 days or be barred from conducting business here. Mayer came aboard in May.

"I understand that the role that I signed up for—including running TikTok globally—will look very different as a result of the U.S. administration's action to push for a sell-off of the U.S. business," he continued in the missive.

GM Vanessa Pappas will serve as interim chief of the company.

Meanwhile, Walmart is teaming with Microsoft on a bid for TikTok.

“We believe a potential relationship with TikTok U.S. in partnership with Microsoft could add this key functionality and provide Walmart with an important way for us to reach and serve omnichannel customers as well as grow our third-party marketplace and advertising businesses,” the retailer said in a statement.

“We are confident that a Walmart and Microsoft partnership would meet both the expectations of U.S. TikTok users while satisfying the concerns of U.S. government regulators.”

CNBC quoted sources saying deal could be announced in coming days, and that the price tag will be in the $20b-$30b range.

Walmart is in the process of building a subscription-based service to better compete with Amazon.