rstudio::conf(2020) call for submissions

This is a companion discussion topic for the original entry at

rstudio::conf, the conference on all things R and RStudio, will take place January 29 and 30, 2020 in San Francisco, Califorrnia, preceded by Training Days on January 27 and 28.
The rstudio::conf program includes invited speakers and RStudio employees, but we also want to hear from you, the R community! We are particularly interested in submissions that have one or more of these qualities:
Showcase the use of R to solve real problems.