ArcGIS Pro 2.8 API Reference Guide
Time Property (MapView)
Example 

ArcGIS.Desktop.Mapping Namespace > MapView Class : Time Property
Gets or sets the time range visible in the map view.
Syntax
public TimeRange Time {get; set;}
Public Property Time As TimeRange
Remarks
This property is null when there are no time aware layers in the map. When the Time property is not null, but both the Start and End properties of the TimeRange are null this means the map view is showing all time. This is equivalent to disabling time in the map view. Setting this property to null when there are time aware layers in the map will set both the start and end properties of the TimeRange to null.
Example
Step forward in time by 1 month in the active map view.
public void StepMapTime()
{
  //Get the active view
  MapView mapView = MapView.Active;
  if (mapView == null)
    return;

  //Step current map time forward by 1 month
  TimeDelta timeDelta = new TimeDelta(1, TimeUnit.Months);
  mapView.Time = mapView.Time.Offset(timeDelta);
}
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

MapView Class
MapView Members