You can easily do that too:
#import "@preview/cheq:0.2.2": checklist
#import "@preview/fontawesome:0.5.0": *
#show: checklist.with(marker-map: (
"x": fa-x(),
))
- [ ] a
- [x] b
Note that the fontawesome package requires you to first manually install the font, since packages can’t ship fonts at the moment. See the package page for instructions: