In ArcMap, the Time slider takes only one layer at a time by design. To create a time animation on multiple layers, merge the layers containing different symbology to a new feature class and use the Time slider on the new layer.
Follow the steps below to create a time animation on multiple layers. It is important to note that features merged must have the same shape type.
Note: The symbology of the new layer is not maintained after merging. If necessary, it must be re-created.
For more information on creating a time animation, refer to: Creating a time animation.
As an alternative, create a group layer in the Table of Contents to make a group layer animation. There are three options that can be set when layers transition from one to the other:
For more information on group layer information, refer to: About making a group layer animation.