The funding for the United States government runs out in just 8 more days -- on April 29th. Unless the Congress and the president can agree on a new budget (won't happen) or a continuing resolution to keep funds flowing, the federal government will shut down again. And considering the mess that is the 115th Congress, I think a shut down is very likely (at least for a few days).
Trump wants any continuing resolution to include money for his border wall and more money for the military, and he wants domestic programs cut to do that. The "freedom caucus" wants Obamacare subsidies and funding for Planned Parenthood eliminated. And the Democrats would oppose all of that. Unless these disparate groups can agree on at least a few months extension, then a shutdown will occur.
Over at Think Progress, Jennifer Scholtes and Sarah Ferris have listed five issues that could result in a shutdown. I think they are right -- any one of these issues could spur a new shutdown. Here are those five issues:
Border wall Blocking grants for “Sanctuary cities” Pentagon boost in spending Eliminating Obamacare subsidies Coal miners’ benefits