I had not realized that Ted Cruz wasn't born in the USA until just the past few days when Donald Trump mentioned it in the media. ( This article in the Washington Post does a good and balanced job explaining the differences between the Cruz birther issue and Obama's.)
Senator Cruz was born in Canada to a mother who is an American citizen and a father who is Cuban and became a US Citizen in 2005. Cruz held dual citizenship until he renounced his Canadian citizenship in 2014. Most legal scholars seem to think that as far as Ted Cruz is concerned, the legality of his eligibility to be President is a moot point, but agree that it has never been tested. As for President Obama who was born in Hawaii to an American mother and Kenyan father, the issue was one of a supposed massive conspiracy and cover up. I sense a bit of passive-aggressive from Mr, Trump, sort of a veiled threat that if Cruz were to be elected, it may be held up in court for years. Whether that is true or not or whether he will lead the charge so to speak is not clear. Time will tell.