Nonprofit from Washington State filed lawsuit against Fox News Channel 

WASHLITE accuses network of 'willfully and maliciously' misleading people 

Lawsuit cites Fox News hosts for dismissing coronavirus as a 'hoax'

Fox News called lawsuit 'frivolous' and vowed to fight it in court 

Sean Hannity claimed he referred to Democrats' criticism of Trump as a 'hoax'

Fox parted ways with Fox Business Network's Trish Regan last week

Regan earlier this month claimed coronavirus was a 'scam' to 'impeach Trump'