I got to see a significant amount of buildings by Helmut Jahn when I lived in Chicago in the late 2010's. My thesis advisor was also one of his trusted employees for a long time, so in some sense I learned a lot from his rigor and ability to execute well-crafted, well thought-out and efficient buildings by proxy. I always had a lot of admiration for his work. His State St. residence on IIT's campus had transformed an unforgiving site (a narrow strip of land between a major street and a very noisy elevated train line) into a very liveable student residence, with the help of some very clever engineering and design decisions.
I was sad to learn that he recently passed away as the result of a fatal cycling accident, but we can find solace in the amazing legacy of buildings and multitude of people he touched on that will carry his legacy of "archi-neering".