Talent agency William Morris Entertainment plans to lay off roughly 20 percent of its employees Monday, in a move that signals the devastation COVID-19 has brought to Hollywood, according to an email from president Ari Greenberg. The agency’s parent company Endeavor has already instituted layoffs, furloughs, and pay cuts for a third of its 7,500-person staff. A source with knowledge of WME’s business told The Daily Beast that the company’s music division would be hardest hit by the cost-saving measures. “As you know, WME is having to make some very difficult decisions to mitigate COVID-19’s effect on our business,” Greenberg opened his email to all WME employees.