This choropleth map visualizes global brain and central nervous system cancer deaths in 2019, with countries colored on a yellow-orange-red sequential scale from the D3 `scaleSequential` and `interpolateYlOrRd` scheme. A legend shows the magnitude of deaths, and hovering over a country reveals its name and total death count via a tooltip. The visualization uses `d3.geoNaturalEarth1` projection and `d3.geoPath` to render country boundaries from TopoJSON world atlas data, merged with CSV datasets for country codes and cancer mortality statistics. The React app loads these data through custom hooks and updates the SVG elements dynamically.