This visualization shows US cancer cases from 2009 to 2022 using a combined line and area chart, with the line stroke in black and the area fill in purple. The code uses D3 v5 (d3.line, d3.area, d3.scaleLinear, d3.axisBottom, d3.axisLeft) with cubic basis curve interpolation (curveBasis) to smooth the chart. Data is loaded from a CSV file via d3.csv, with numeric parsing for cases and year. The SVG renders axes with gridlines, axis labels, and a title.