public sealed class ActiveTemplateChangedEventArgs : System.EventArgs 

ArcGIS.Desktop.Editing.Events.ActiveTemplateChangedEvent.Subscribe(OnActiveTemplateChanged);

async void OnActiveTemplateChanged(ArcGIS.Desktop.Editing.Events.ActiveTemplateChangedEventArgs args)
{
  // return if incoming template is null
  if (args.IncomingTemplate == null)
    return;

  // Activate two-point line tool for Freeway template in the Layers map
  if (args.IncomingTemplate.Name == "Freeway" && args.IncomingMapView.Map.Name == "Layers")
    await args.IncomingTemplate.ActivateToolAsync("esri_editing_SketchTwoPointLineTool");
}