public static IList<ColorRampStyleItem> SearchColorRamps( 
   StyleProjectItem styleProjectItem,
   string searchString
)

public async Task<IList<ColorRampStyleItem>> GetColorRampsFromStyleAsync(StyleProjectItem style, string searchString)
{
  //StyleProjectItem can be "ColorBrewer Schemes (RGB)", "ArcGIS 2D"...
  if (style == null)
    throw new System.ArgumentNullException();

  //Search for color ramps
  //Color Ramp searchString can be "Spectral (7 Classes)", "Pastel 1 (3 Classes)", "Red-Gray (10 Classes)"..
  return await QueuedTask.Run(() => style.SearchColorRamps(searchString));
}

public async Task ApplyColorRampAsync(FeatureLayer featureLayer, List<string> fields)
{

    StyleProjectItem style =
        Project.Current.GetItems<StyleProjectItem>()
            .FirstOrDefault(s => s.Name == "ColorBrewer Schemes (RGB)");
    if (style == null) return;
    var colorRampList = await QueuedTask.Run(() => 
                style.SearchColorRamps("Red-Gray (10 Classes)"));
    if (colorRampList == null || colorRampList.Count == 0) return;
    CIMColorRamp cimColorRamp = null;
    CIMRenderer renderer = null;
    await QueuedTask.Run(() =>
    {
        cimColorRamp = colorRampList[0].ColorRamp;
        var rendererDef = new UniqueValueRendererDefinition(fields, null, cimColorRamp);
        renderer = featureLayer?.CreateRenderer(rendererDef);
        featureLayer?.SetRenderer(renderer);
    });

}

string colorBrewerSchemesName = "ColorBrewer Schemes (RGB)";
StyleProjectItem style = Project.Current.GetItems<StyleProjectItem>().First(s => s.Name == colorBrewerSchemesName);
string colorRampName = "Greens (Continuous)";
IList<ColorRampStyleItem> colorRampList = await QueuedTask.Run(() =>
{
  return style.SearchColorRamps(colorRampName);
});
ColorRampStyleItem colorRamp = colorRampList[0];

await QueuedTask.Run(() =>
{
  GraduatedColorsRendererDefinition gcDef = new GraduatedColorsRendererDefinition()
  {
    ClassificationField = "CROP_ACR07",
    ClassificationMethod = ArcGIS.Core.CIM.ClassificationMethod.NaturalBreaks,
    BreakCount = 6,
    ColorRamp = colorRamp.ColorRamp,
    SymbolTemplate = SymbolFactory.Instance.ConstructPolygonSymbol(
                            ColorFactory.Instance.GreenRGB, SimpleFillStyle.Solid, null).MakeSymbolReference(),
    ExclusionClause = "CROP_ACR07 = -99",
    ExclusionSymbol = SymbolFactory.Instance.ConstructPolygonSymbol(
                            ColorFactory.Instance.RedRGB, SimpleFillStyle.Solid, null).MakeSymbolReference(),
    ExclusionLabel = "No yield",
  };
  var featureLayerCreationParams = new FeatureLayerCreationParams((new Uri(@"c:\Data\CountyData.gdb\Counties")))
  {
    Name = "Crop",
    RendererDefinition = gcDef
  };
  LayerFactory.Instance.CreateLayer<FeatureLayer>(featureLayerCreationParams, MapView.Active.Map);
});

//Must be called on the MCT
//var pcsl = ...;

//At 2.x - var fields = pcsl.QueryAvailablePointCloudRendererFields(
//                           PointCloudRendererType.StretchRenderer);

var fields = pcsl.GetAvailablePointCloudRendererFields(
                         PointCloudRendererType.StretchRenderer);
var stretchDef = new PointCloudRendererDefinition(
                          PointCloudRendererType.StretchRenderer)
{
  //Will be either ELEVATION or INTENSITY
  Field = fields[0]
};
//Create the CIM Renderer
var stretchRenderer = pcsl.CreateRenderer(stretchDef) 
                                   as CIMPointCloudStretchRenderer;
//Apply a color ramp
var style = Project.Current.GetItems<StyleProjectItem>()
                                .First(s => s.Name == "ArcGIS Colors");
var colorRamp = style.SearchColorRamps("").First();
stretchRenderer.ColorRamp = colorRamp.ColorRamp;
//Apply modulation
stretchRenderer.ColorModulation = new CIMColorModulationInfo()
{
  MinValue = 0,
  MaxValue = 100
};
//apply the renderer
pcsl.SetRenderer(stretchRenderer);