This interactive chloropleth map visualizes global deaths from brain and central nervous system cancer in 2019, using a yellow-to-red sequential color scale via `d3.scaleSequential` and `d3.interpolateYlOrRd`. A `d3.geoNaturalEarth1` projection renders country boundaries from the World Atlas TopoJSON, with each country’s fill determined by matching ISO country codes from a CSV to cancer mortality data. Users hover over a country to display its name and total deaths in a floating tooltip, while a legend shows the color scale range. The visualization uses React for state management, `d3.geoPath` for drawing, and `topojson.feature` for geographic data processing.