Sen. Marco Rubio called the death of Cuba’s former leader Fidel Castro a "historical milestone" and recommended President-elect Donald Trump not retroactively remove protections for undocumented immigrants established by the Obama administration in an appearance on NBC’s “Meet the Press” on Sunday.

Rubio, R-Fla., also weighed in on Trump’s transition to the White House and declined to publicly support Trump’s nominee for Attorney General.

Additionally, he commented on the need for a congressional look into the WikiLeaks hacks.

CUBA

A Cuban-American himself, Rubio reacted to the death of Fidel Castro over the weekend, saying it was a "historical milestone" and a "psychological" milestone "for a lot of people."

Rubio, who has been critical of Pres. Obama’s actions on Cuba, said he wants to “look at all the changes that were made,” while adding that “our goal is not to punish” Cubans.

A portrait of Fidel Castro is surrounded by flowers outside Cuba's embassy in Santiago, Chile. Esteban Felix / AP

“I have never said that I’m against all changes to Cuba policy," he added. "I’m just against unilateral changes from which we get nothing in return for our country or for the freedom or liberty of the Cuban people."

DACA

President-elect Donald Trump has promised to roll back many of President Obama’s executive orders, drawing concerns from undocumented immigrants who have been protected by the Deferred Action for Childhood Arrivals (DACA) program.

Rubio said he would recommend that Trump not “retroactively remove their status” but he also said people should not be allowed to apply for renewal.

"People already have it, so someone has that DACA permit but it is not indefinite, it expires," he said. "And what I would say is if you have it, then you have it for the remainder of that period of time but you will not be able to renew it."

That time is needed, Rubio said, for "border security, modernization" and to then move to a more "reasonable" system “for people like those who came here as children, or those who have been here for a long time who are not criminals, to allow them to attain some legal status through a legal way — not an unconstitutional way, which is what DACA is.”

Related: Professors, Students 'Uncertain' About Futures of Undocumented Peers

TRANSITION APPOINTMENTS

On appointments to President-elect Trump’s incoming administration, Rubio has offered public praise of Rep. Mike Pompeo as CIA director and Gov. Nikki Haley as UN Ambassador, but not for fellow Senator Jeff Sessions for Attorney General.

Rubio explained Pompeo’s and Haley’s nominations will both come through committees he sits on, before they reach the full Senate, while Sessions’ nomination will not.

Rubio was not ready to say publicly if he’ll support Sessions’ confirmation: “No, I never do, until that person works their way through the process.”

WIKILEAKS

During the campaign, Rubio was outspoken on the issue of the WikiLeaks hacks, warning fellow Republicans, saying, “Today it is the Democrats. Tomorrow it could be us.”

On Sunday, Rubio said the hacks were “absolutely” worthy of Congressional scrutiny.

Related: Kremlin Says Russians Met Trump Staff; Campaign Denies It

Asked if the Foreign Relations subcommittee he chairs would investigate, Rubio said, “We’d need the permission of the full committee, and I imagine that Senator Corker may have an opinion on that. He may himself want to do that. You’ll have to ask him.”

Rubio continued, “If a foreign government has been involved in injecting chaos into our democratic process, the American people deserve to know that.”

While declining to blame the Russian government directly, Rubio said what happened during the U.S. election was "very similar to the sort of active measures that you’ve seen the Russians use in the past in places like Eastern Europe, to interfere with the elections of other countries…they try to undermine the credibility of the election. They try to undermine individual leaders."