I know a number of people have reached out to Rubio personally, myself included, to suggest it was time to stand down.
The Rubio campaign has been very insistent all day that Rubio is staying in the race because of Florida, despite that fact that his continued presence on March 15th will hurt Ted Cruz in a number of other states he could otherwise take from Trump.
Nonetheless, there is more and more buzz this afternoon that the Rubio campaign is winding down. Fox News has run several reports today about Rubio dropping out, but the campaign has continued to deny it.
According to the Rubio website, he has one event scheduled in Florida. It is today at 5pm ET. There are no other events listed.
Perhaps he will make an announcement there.