Available with Location Referencing license.
Why is the Location Referencing tab not showing up when I import an ArcMap project with LRS layers into ArcGIS Pro?
The migration of projects created in beta versions of ArcGIS Pipeline Referencing is not supported. You will not see the Location Referencing tab in projects that were created with Pipeline Referencing Beta 1 or 2. To see the tab, you need to open the project in ArcGIS Pro 1.4 and add an LRS-related feature class (Centerline, CalibrationPoint, or Network).