The final Republican debate before the Iowa caucuses will only feature two candidates — former U.S. Ambassador to the United Nations Nikki Haley and Florida Gov. Ron DeSantis  — said CNN, the host of the Jan. 10 debate. 

CNN announced Tuesday that only Haley, DeSantis and former President Donald Trump have qualified. But Trump, who has skipped the earlier four debates, is opting instead for a FOX News town hall in Iowa at the same time that night, FOX announced Tuesday. 

Businessman Vivek Ramaswamy and former New Jersey Gov. Chris Christie, who both participated in the last debate in December, did not meet CNN's qualification thresholds. Neither did former Arkansas Gov. Asa Hutchinson.

Ramaswamy posted on X on Tuesday after he failed to qualify that he will be doing a live-audience show the same night of the debate with journalist Tim Pool. He also slammed CNN, some of its reporters, hosts, and commentators calling them "shenanigans" and criticized their reporting towards him.   

Haley blasted Trump for declining to face his opponents.

"With only three candidates qualifying, it's time for Donald Trump to show up," Haley said in a statement. "As the debate stage continues to shrink, it's getting harder for Donald Trump to hide."

The Republican National Committee isn't taking part in the Jan. 10 GOP primary debate, or in any debates to follow, saying it's up to the candidates if they want to participate. 

When is the CNN debate?

The CNN debate is set to take place at 9 p.m. ET on Jan. 10 at Drake University in Des Moines, Iowa.   

Who is leading in polls in Iowa? 

Iowa's status as the first state to hold a nominating contest has long made the Hawkeye State a key prize for presidential candidates, and most Republicans have been hitting the campaign pavement with frequent events there.   

Haley has gained on Trump in the polls in New Hampshire, but in Iowa, Trump is the easy favorite over Haley and DeSantis, according to a recent CBS News poll. A December CBS News/YouGov poll in Iowa shows Trump with 58% support among likely GOP caucus goers, over DeSantis's 22% Haley's 13%.   

Kathryn Watson is a politics reporter for CBS News Digital based in Washington, D.C.