On the left, the four lines are the historical policy rates from G4 central banks (the U.S., euro area, UK and Japan). In the case of the UK, Japan and euro area, policy rates have remained low for much of the post-global financial crisis era. The U.S. and UK are have been raising rates this year again after learning to live with the virus and facing considerable inflation pressure.
On the right, the four lines show market expectation of where policy rates would be in coming years. Investors are reflecting a more hawkish sentiment with the U.S. Federal Reserve, the Bank of England and the European Central Bank, with policy rate hikes in 2022 and for rates to stay high through mid-2023. The Bank of Japan, however, is still a ways off from any meaningful tightening.