Note this is not an indefinite block, just a pain for Republicans. They can’t permanently block anything without republican votes, but they can at least drag it out

Senators have the power to invoke a hold on a presidential nominee, a maneuver that can slow or stall consideration of a nominee for days or weeks. Precious Senate floor time is often needed to overcome holds on presidential nominees.

Hopping we see more of this following Booker’s 25hr filibuster