The Moving average convergence divergence is a trend indicator because it helps to predict if the trend is going to change. In this case, there is a uptrend line (yellow line) and before we know is going to break we can see the divergence between the two blue lines. On chart, the blue dark line is indicating that there are higher highs and lows and the blue line below (MACD) is indicating that there are lower highs, suggesting it is going to break the trend line.