Three federal byelections could mark an important milestone for the Carney Liberals. One win would mean the Liberals would have a majority government. 

We look at what’s at stake in today’s vote.

And: The U.S. has imposed a naval blockade on Iran. It went into effect today, after this weekend's talks between the United States and Iran collapsed. The shaky ceasefire is still in effect for another week.  

Also: Cancer is still the leading cause of death in Canada. Despite more screening and prevention tools, numerous types of cancer are increasing, according to a new study.

Plus: Drug crisis in British Columbia, Trump vs. the Pope, Ontario restructures school boards, and more.