Former Trump adviser Roger Stone says he will "fully comply" with the Senate intelligence committee's request for information and documents relating to its Russian Federation investigation.
The scope of the committee's investigation includes looking into whether any members of the 2016 presidential campaigns had ties to Russian Federation.
Committee chairman Republican Richard Burr had previously warned he would issue subpoenas for those who did not cooperate with the investigation.
Flynn is one of four former Trump aides that Senate investigators sent requests to.
Gen Flynn was forced to resign in February as Trump's national security adviser for failing to disclose the content of his talks with Mr Sergey Kislyak, Russia's ambassador to the USA, and then misleading Vice-President Mike Pence about the conversations.
It will be McCabe's first public appearance since Trump fired Director James Comey, calling into question the future of the the FBI's own investigation into possible collusion between Russian Federation and Trump campaign associates.
Earlier this week CNN reported that grand jury subpoenas were issued to several of Flynn's business associates.
Flynn's lawyer did not immediately respond to questions from Newsweek about whether Flynn plans to respond to the legal order and how many documents he has relating to the investigation. McCabe was testifying in place of former FBI Director James Comey, who was sacked by President Donald Trump on Tuesday.
"The first thing we did was to explain to Mr. McGahn that the underlying conduct that Gen. Flynn has engaged in was problematic in and of itself", Yates said.