Question about ASO

I’m using sensor tower to track the keywords for my competitor apps.
I realized that they targeted a long list of keywords.
But apparently their app description is quite short and some of these
keywords are not appearing in the app description.
Anyone has any idea why they are able to target these keywords
when they do not have them in the app description in the first place?
Is there something got to do with the reviews?
Thank you.

reviews,link building,social sharing over the net etc etc etc.