Montana held primaries on June 2 for the Democratic, Republican, and Green Parties. The Libertarian Party is also on the ballot, but it had no contests so the state didn’t print Libertarian primary ballots.
The Green Party primary for U.S. Senate had two candidates, Wendie Fredrickson and Dennis Daneke. The Montana Green Party considers both of them non-members and didn’t want to have any nominee for Senate. Fredrickson won the primary by two-to-one. It is thought that Fredrickson is a sympathizer of the Republican Party, and it is known that Daneke is a supporter of the Democratic Party. Daneke had said if he won the primary, he would withdraw, because he supports the Democratic nominee. Here is a link to the Secretary of State’s website, showing the election returns.