Animation
Activate this option if animations are to be imported. You can see what kind of animations can be imported here: What kind of animations can the USD import/export handle?
This option corresponds to the Clean Tracks command of the same name in the timeline. When importing, many adjacent keys with the same key values are reduced to the first and last of the identical keys.
This setting is about loading "USD skeletons", which are imported into Cinema 4D as joint hierarchies with weightings and skin objects - i.e., the basis of a character animation.
If the option is activated, these are imported, otherwise they are omitted. Tracks and Skin should therefore both be activated if you want to import character animations - if Tracks are deactivated, only joints/skin objects are imported without any animation tracks.