Solo a layer

You can isolate one or more layers for animating, previewing, or final output by soloing. Soloing excludes all other layers of the same type from being rendered—both for previews in the Composition panel and for final output. For example, if you solo a video layer, any lights and audio layers are unaffected, so they appear when you preview or render the composition. However, the other video layers do not appear.

To solo one or more layers, select the layers in the Timeline panel, and click the Solo icon to the left of the layer names.
To solo one layer and unsolo all other layers, Alt-click (Windows) or Option-click (Mac OS) the Solo icon to the left of the layer name.

The Video switch is dimmed for other layers when a layer is soloed, indicating that the other layers are not visible.