The Bonds vs Stocks ratio is a very important tool to gauge the current trend of the market. Money rotates between assets and when money is flowing into bonds it is bullish for Bonds and Bearish for Equities. The reverse also holds true.
See the chart below.
The chart shows the ratio of diversified bonds vs equites. See how it spiked above the 50 month moving average in the 2008 Financial crisis. since then it has been trending lower and well below the moving average. In 2020 March it went up for a short while but has come below and is near all time lows. This shows the current trend is Bullish for Equities. Any risk on environment, this ratio will start trending upwards and be an early warning signal.
For a long term bear market it will sustain above the average. Till then the odds are in favour of a continued bull market in Equities.