The CARE Act was signed by President Trump on Friday, March 27, 2020 and is now law. The bill is hundreds of pages so this is not a comprehensive list but contains a list of the most popular provisions.
Here is a link to the complete bill details.
Many states have changed their due dates so please verify all state due dates over the next few weeks. Here is a link to the most up to date due dates for states: State Tax Deadline Changes