Comment by DonHopkins

Unfortunately it was cancer from the radiation of atomic bomb tests that killed John von Neumann far too early, not his experiments with cellular automata.

https://www.hnf.de/en/permanent-exhibition/exhibition-areas/...

https://en.wikipedia.org/wiki/Von_Neumann_cellular_automaton

https://en.wikipedia.org/wiki/Von_Neumann_universal_construc...