public class CIMChartHistogramSeries : CIMChartSeries, System.ComponentModel.INotifyPropertyChanged, System.Xml.Serialization.IXmlSerializable  

// For more information on the chart CIM specification:
// https://github.com/Esri/cim-spec/blob/main/docs/v2/CIMCharts.md

var lyrsHistogram = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>();
var lyrHistogram = lyrsHistogram.First();
var lyrDefHistogram = lyrHistogram.GetDefinition();

// Get list names for fields of type Double
var doubleFields = lyrHistogram.GetFieldDescriptions().Where(f => f.Type == FieldType.Double).Select(f => f.Name);

// Create list that will contain all histograms
var histograms = new List<CIMChart>();

// Create histogram for each Double field
foreach (var field in doubleFields)
{
    // Define histogram CIM properties
    var histogram = new CIMChart
    {
        Name = $"histogram_{field}",
        GeneralProperties = new CIMChartGeneralProperties
        {
            Title = $"Histogram for {field}",
        },
        Series = new CIMChartSeries[]
        {
        new CIMChartHistogramSeries {
            UniqueName = "histogramSeries",
            Name = $"histogram_{field}",
            BinCount = 15,
            // Specify the number field
            Fields = new string[] { field },
        }
        }
    };


    histograms.Add(histogram);
};

// Add new chart to layer's existing list of charts (if any exist)
var allChartsHistogram = (lyrDefHistogram == null) ? histograms : lyrDefHistogram.Charts.Concat(histograms);
// Add CIM chart to layer defintion 
lyrDefHistogram.Charts = allChartsHistogram.ToArray();
lyrHistogram.SetDefinition(lyrDefHistogram);