A German theatre chain, and other sources, reported this will be out April 1st 2020. So I guess that goes for the US as well then. IMDb still has it marked as 'in development' but I'm sure that's not up-to-date. Here are some sources: http://www.cinestar.de/film/fools-day and http://www.insidekino.com/DStarts/DStartplan.htm . The second one is very reliable, the first one should be as well since it's a well known chain. Insidekino have all the correct information on when films start in Germany before all others, in my experience. I look everything up over there all the time.