The busiest slate of confirmation hearings so far kicks off on Thursday morning.

Secretary of State nominee Rex Tillerson will not return — as was scheduled — for another day of testimony after a grilling on Wednesday before the Senate Foreign Relations Committee.

But two other foreign affairs nominees will face Russia questions of their own when they go to the Senate on Thursday: CIA nominee Rep. Mike Pompeo (R-Kan.) and retired Marine Gen. James Mattis, President-elect Donald Trump Donald John TrumpBarr criticizes DOJ in speech declaring all agency power 'is invested in the attorney general' Military leaders asked about using heat ray on protesters outside White House: report Powell warns failure to reach COVID-19 deal could 'scar and damage' economy MORE’s Defense Secretary pick.

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Rounding out the slate is former GOP presidential candidate Ben Carson, nominated to head the Department of Housing and Urban Development.

Here’s what to watch for on day three of the confirmation hearings:

More Russia on tap

After both Republicans and Democrats picked apart Tillerson's views on Russia during a marathon hearing Wednesday, more Trump picks could get a similar treatment Thursday.

Democrats will try to corner Pompeo on the president-elect’s continued denial of Russian interference in the election.

The panel’s ranking member, Sen. Mark Warner Mark Robert WarnerIntelligence chief says Congress will get some in-person election security briefings Overnight Defense: Trump hosts Israel, UAE, Bahrain for historic signing l Air Force reveals it secretly built and flew new fighter jet l Coronavirus creates delay in Pentagon research for alternative to 'forever chemicals' House approves bill to secure internet-connected federal devices against cyber threats MORE (D-Va.), is expected to push Trump’s nominee to head the CIA on what he’ll do to convince Trump to get on board with the intelligence community’s assessment.

Sen. Dianne Feinstein Dianne Emiel FeinsteinSenators offer disaster tax relief bill Democrats back away from quick reversal of Trump tax cuts Congress must save the Postal Service from collapse — our economy depends on it MORE (D-Calif.) has been outspoken on the issue as well, condemning the intrusions as an attack on democracy.

The questioning could put Pompeo in a tricky position: He’ll have to reassure jumpy lawmakers that he takes the threat from Russia seriously, while avoiding criticizing the man who appointed him.

Likely supercharging the debate is the explosive but unconfirmed report suggesting members of the Trump team had contact with Russia during the campaign.

Pompeo has earned bipartisan praise from his colleagues on the House Intelligence Committee as a hard-working lawmaker with a sophisticated grasp of policy. That likely will diffuse some of the fireworks that could have come from his hearing.

Mostly friendly faces for Mattis

Trump’s nominee to lead the Department of Defense will face a friendly crowd, as well. He’s well-known on Capitol Hill and has a good relationship with many senators.

Even so, members are likely to sharply probe how he’ll advise Trump on Russia from the Pentagon.

He’ll have other issues to grapple with as well when he goes before the Armed Services Committee: the Islamic State of Iraq and Syria, defense spending, torture, Iran and Afghanistan are likely to come up.

Other issues that concern individual senators, such as sexual assault in the military and servicewomen in combat roles may also come up.

Mattis may have sown seeds of contention Wednesday by canceling a planned Thursday afternoon appearance before the House Armed Services Committee.

That panel had requested Mattis's testimony because House members will vote on a waiver for him to circumvent a law that requires the top Defense official to have been out of uniform for at least seven years.

That vote could come as soon as Friday. Should opposition emerge, it would be largely symbolic because the Republican majority can push the waiver through.

Carson comes on the stage

Democrats are likely to be more aggressive with Trump’s pick to head the Department of Housing and Urban Development (HUD).

Trump picked Carson as his HUD nominee in December, despite the fact that the retired neurosurgeon and former presidential candidate had at one point cited his lack of experience as a reason not to accept a Cabinet position.

The pick confused Democrats and angered housing advocates: Carson made his name as a pediatric neurosurgeon, not through urban issues, so he’s likely to be grilled on how he will handle federal housing policy and urban economics.

Carson’s positions on housing policy — he opposed a key Obama rule mandating reports on racial bias in housing — and Trump’s statements about crime in urban areas are likely to provide fodder for the Senate Banking, Housing and Urban Affairs Committee.

But his lack of experience is likely to be the biggest sticking point — and it’s something outside groups have seized on.

“With many qualified Republicans to choose from with deep knowledge of, and commitment to, affordable housing solutions for the poorest families … Dr. Carson’s nomination to serve as HUD Secretary is surprising and concerning,” National Low Income Housing Coalition President Diane Yentel said in a statement after his nomination.

Where’s Wilbur?

Senators were scheduled to hear from a fifth nominee on Thursday, but a delay in ethics filings has created another delay.

Wilbur Ross, a billionaire investor picked by Trump to lead the Commerce Department, has not filed the required conflict of interest paperwork with the Office of Government Ethics. The GOP said Tuesday it would give him more time and pushed his hearing to next week.

Republicans rescheduled a handful of confirmation hearings originally slated for this week, amid Democratic complaints that the process was moving too quickly. Hearings for Education secretary (Betsy DeVos) and Labor secretary (Andrew Puzder) were also scheduled this week and delayed, ensuring a busy week for lawmakers next week ahead of Trump’s Jan. 20 inauguration.

Katie Bo Williams and Kristina Wong contributed.