public sealed class MapProjectItem : ArcGIS.Desktop.Internal.Catalog.ProjectItemInfoCrawl, ArcGIS.Desktop.Core.IMetadata, ArcGIS.Desktop.Core.IProjectItem, ArcGIS.Desktop.Core.ISearchableItem, System.ComponentModel.INotifyPropertyChanged, System.IDisposable  

{
  // not to be included in sample regions
  var projectFolderConnection = Project.Current.GetItems<FolderConnectionProjectItem>().First();

  // Get all the maps in a project
  IEnumerable<MapProjectItem> projectMaps = Project.Current.GetItems<MapProjectItem>();
}

{
  // Remove a map from a project; the map is deleted
  IProjectItem mapToRemove = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(map => map.Name.Equals("OldStreetRoutes"));
  // Note: Needs QueuedTask to run
  var removedMapProjectItemResult = Project.Current.RemoveItem(mapToRemove);
  // Use removedMapProjectItemResult
}

{
  var project = Project.Current;
  IEnumerable<MapProjectItem> newMapItemsContainer = project.GetItems<MapProjectItem>();
  // Note: Needs QueuedTask to run
  foreach (var mp in newMapItemsContainer)
  {
    //Do Something with the map. For Example:
    Map myMap = mp.GetMap();
  }
}

{
  MapProjectItem mapProjItem = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(item => item.Name.Equals("EuropeMap"));
  // Use mapProjItem;
}

{
  //GetItems searches project content
  var map = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(m => m.Name == "Map1");
  var layout = Project.Current.GetItems<LayoutProjectItem>().FirstOrDefault(m => m.Name == "Layout1");
  var folders = Project.Current.GetItems<FolderConnectionProjectItem>();
  var style = Project.Current.GetItems<StyleProjectItem>().FirstOrDefault(s => s.Name == "ArcGIS 3D");

  //Find item uses a catalog path. The path can be to a file or dataset
  var fcPath = @"C:\Pro\CommunitySampleData\Interacting with Maps\Interacting with Maps.gdb\Crimes";
  var pdfPath = @"C:\Temp\Layout1.pdf";
  var imgPath = @"C:\Temp\AddinDesktop16.png";

  var fc = Project.Current.FindItem(fcPath);
  var pdf = Project.Current.FindItem(pdfPath);
  var img = Project.Current.FindItem(imgPath);
}

{
  //Create a map frame and set its camera by zooming to the extent of an existing bookmark.
  //Construct on the worker thread

  //Build 2D envelope geometry
  Coordinate2D mf_ll = new Coordinate2D(6.0, 8.5);
  Coordinate2D mf_ur = new Coordinate2D(8.0, 10.5);
  Envelope mf_env = EnvelopeBuilderEx.CreateEnvelope(mf_ll, mf_ur);

  //Reference map, create MF and add to layout
  MapProjectItem mapPrjItem = Project.Current.GetItems<MapProjectItem>()
                       .FirstOrDefault(item => item.Name.Equals("Map"));
  Map mfMap = mapPrjItem.GetMap();
  Bookmark bookmark = mfMap.GetBookmarks().FirstOrDefault(
                        b => b.Name == "Great Lakes");

  MapFrame mfElm = ElementFactory.Instance.CreateMapFrameElement(
                       layout, mf_env, mfMap, "New Map Frame");

  //Zoom to bookmark
  mfElm.SetCamera(bookmark);
}

{
    //Finding the first project item with name matches with mapName
    MapProjectItem? mpi = Project.Current.GetItems<MapProjectItem>()
      .FirstOrDefault(m => m.Name.Equals("The Map", StringComparison.CurrentCultureIgnoreCase));
    //Note: Needs QueuedTask to run
    var mapFromItem = mpi?.GetMap();
    if (mapFromItem != null)
    {
        //Open the map in a new map pane
        //Must be called from the UI thread
        await ProApp.Panes.CreateMapPaneAsync(map);
    }
}

{
  string openProjectPath = @"D\DATA\IGPHistoryItemTestProject\IGPHistoryItemTestProject.aprx";
  Project.OpenAsync(openProjectPath);
  MapProjectItem mapProjItem = Project.Current.GetItems<MapProjectItem>().FirstOrDefault(item => item.Name.Equals("Map", StringComparison.CurrentCultureIgnoreCase));

  // Note: Needs QueuedTask to run
  var map = mapProjItem.GetMap();
  var ftrLayer = map.Layers[0] as FeatureLayer;
  string tool1 = "management.GetCount";
  var args1 = Geoprocessing.MakeValueArray(ftrLayer);
  var env = Geoprocessing.MakeEnvironmentArray(overwriteoutput: true);
  GPExecuteToolFlags executeFlags = GPExecuteToolFlags.AddToHistory;
  var t = Geoprocessing.ExecuteToolAsync(tool1, args1, env, null, null, executeFlags);

  IEnumerable<IGPHistoryItem> hisItems = Project.Current.GetProjectItemContainer(Geoprocessing.HistoryContainerKey) as IEnumerable<IGPHistoryItem>;

  string hitemID = "";
  string hitemToolPath = "";
  IGPResult hitemGPResult = null;
  DateTime hitemTimeStamp;

  foreach (var hitem in hisItems)
  {
    // common IGPHistoryItem and Item properties
    hitemID = (hitem as Item).ID;
    hitemToolPath = hitem.ToolPath;
    hitemGPResult = hitem.GPResult;
    hitemTimeStamp = hitem.TimeStamp;

    // use the properties as needed
  }
}