Scholze's win has been predicted for quite a while now, as it turns out. He's a number theorist of stunning originality primarily known for developing a new kind of geometry, that of perfectoid spaces, for arithmetic purposes.

Here's an interview with him that will be accessible to nonspecialists:

https://www.youtube.com/watch?v=J0QdTYZIfIM

At a higher level, here's an appraisal of his work by a professional in a closely related area:

  It's not often that contemporary mathematics provides such a clear-cut example
  of concept formation as the one I am about to present:  Peter Scholze's
  introduction of the new notion of perfectoid space. The 23-year old Scholze
  first unveiled the concept in the spring of 2011 in a conference talk at the
  Institute for Advanced Study in Princeton.  I know because I was there.  This
  was soon followed by an extended visit to the Institut des Hautes Études
  Scientifiques (IHES) at Bûres- sur-Yvette, outside Paris — I was there too.
  Scholze's six-lecture series culminated with a spectacular application of the
  new method, already announced in Princeton, to an outstanding problem left over
  from the days when the IHES was the destination of pilgrims come to hear
  Alexander Grothendieck, and later Pierre Deligne, report on the creation of the
  new geometries of their day.  Scholze's exceptionally clear lecture notes were
  read in mathematics departments around the world within days of his lecture —
  not passed hand-to-hand as in Grothendieck's day — and the videos of his talks
  were immediately made available on the IHES website.  Meanwhile, more killer
  apps followed in rapid succession in a series of papers written by Scholze,
  sometimes in collaboration with other mathematicians under 30 (or just slightly
  older), often alone.  By the time he reached the age of 24, high-level
  conference invitations to talk about the uses of perfectoid spaces (I was at a
  number of those too) had enshrined Scholze as one of the youngest elder
  statesmen ever of arithmetic geometry, the branch of mathematics where number
  theory meets algebraic geometry.)  Two years later, a week-long meeting in 2014
  on Perfectoid Spaces and Their Applications at the Mathematical Sciences
  Research Institute in Berkeley broke all attendance records for "Hot Topics"
  conferences.

- Michael Harris, "The Perfectoid Concept: Test Case for an Absent Theory"

https://www.math.columbia.edu/~harris/otherarticles_files/pe...