How to add a shapefile (Brazil's contour map) into my existing plot?

Hello masters,

I already have a map showing the metrics among a precipitation estimation versus observed precipitation. But i need to put the contourmap of Brazil on it. Because without it, it is strange to show. I have a shapefile for that and I can read with the SHAPEREAD function and open with MAPSHOW.

But how can I add it into an existing map?

Best regards! Thanks a lot!