Joe Biden told reporters that he is thinking about running 2020 after telling them he absolutely was going to run:

NEWS. @vp Biden tells small group of reporters he may run for president in 2020. “Yeah I am. I am going to run in 2020"

From the Washington Examiner:

Vice President Joe Biden indicated Monday that he could be open to running for the White House in 2020.

“I am going to run in 2020,” Biden said when asked by reporters on Monday whether he would run again.

Reporters asked Biden several times to clarify his statement, which seemed like it might have been a joke. “Just to be clear, were you kidding about running for president in 2020?” a reporter asked.