The IRS, on March 18, 2020, issued guidance providing it would waive penalties and interest on tax payments for 90 days, though not postponing the due date for filing a 2019 tax return.
On March 20, 2020, US Treasury Secretary Steven Mnuchin announced via Twitter that the IRS and Treasury have delayed the due date for filing 2019 tax returns to July 15, 2020. (Please note that Twitter is not an official publication vehicle of the US Government, though it certainly appears to be used as such by its Commander in Chief.)
US Persons who are not present in the US have an automatic extension of 60 days to file the US return. This would mean that US Persons in Canada on April 15, 2020 would have an automatic extension to file on or before June 15, 2020 and an extension to pay on or before July 15, 2020.
As the situation is still fluid, please stay tuned in case the situation changes.