Coming up Sunday: A new CBS News Battleground Tracker poll looks at the 2016 presidential race in early primary & caucus states, and Republican candidates Donald Trump and Ben Carson

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U.S. presidential hopeful Donald Trump speaks during a press availability at Trump Tower in Manhattan, New York September 3, 2015.

REUTERS/Lucas Jackson

Donald Trump continued his combative approach to running for president this week, directing fresh criticism at some other outsider candidates in the Republican field. He labelled retired neurosurgeon Ben Carson "an OK doctor" and "not a great religious figure" during an appearance on CNN Thursday, and he mocked former Hewlett-Packard CEO Carly Fiorina's business experience and her "face" during an interview with Rolling Stone (though he later clarified he was talking only about her "persona").

Meanwhile, both the Democratic and Republican primary battles are heating up, with some surging candidates in both parties threatening the frontrunners.

We'll talk with Trump about the state of the Republican race and how he plans on taking the fight to his competitors as the primary wears on.

We'll also talk with Carson, who's emerging as one of the strongest competitors to Trump, about how he hopes to build on his momentum.

On the Democratic side, we'll chat with Democratic strategist and CNN senior political commentator David Axelrod about whether former Secretary of State Hillary Clinton should really feel threatened by the rise of Vermont Sen. Bernie Sanders.

And we'll have some new numbers from the CBS News 2016 Battleground Tracker poll to help us make sense of the election, with some expert analysis from CBS News Elections Director Anthony Salvanto on how voters in Iowa, New Hampshire, and South Carolina are responding to the candidates.

Our panel -- featuring Peter Baker of the New York Times, Wall Street Journal and CBS News contributorPeggy Noonan, John Heilemann of Bloomberg Politics, and Gwen Ifill of the PBS Newshour and Washington Week - will unpack the week's political stories.

And in our weekly "Field Notes," John Dickerson will examine Vice President Joe Biden's recent admission that his son Beau's passing has left him unsure whether he has the emotional capacity for a presidential bid.

We hope you'll join us. Check your local listings.