There is an interest in the right's conspiracy theory
Tucker Carlson claimed on the air that the National Security Agency was monitoring his electronic communications as part of a scheme to take his show off the air. The host offered no proof, but several congressional Republicans were behind him. The top Republican on the Senate Intelligence Committee isn't aware of any wrongdoing on the part of the intelligence community, but he is aware of the "perceptions."
The National Security Agency issued a statement after Carlson raised the allegations, explaining that the Fox News personality has never been an intelligence target and that the agency has never planned to take his program off the air. The spy agency has a foreign intelligence mission. The conservative host has a history of making false or exaggerated claims according to the NBC News report.
The basis of Carlson's accusation is that the government was aware of his outreach. The National Security Agency was not monitoring Carlson's communications, but the communications of the person Carlson was talking to. If you connected with a member of Putin's team, the National Security Agency would probably be aware of that.
Donald Trump's insistence that U.S. intelligence agencies "spied on" him was reminiscent of this. When pressed for proof, Republicans have pointed to instances in which members of Team Trump were in communication with their Russian allies. But again, this wasn't because anyone was snooping on the Trump campaign, it was because U.S. intelligence agencies were snooping on Russians.
It is possible that the ambitious Republican is playing a partisan political game, so that he can tell his party's base and conservative media that he has uncovered relevant information.