There will default shortcuts in 3.1 (see Debugger keyboard shortcuts by mnowacki-b · Pull Request #9154 · jupyterlab/jupyterlab · GitHub and Debugger: show button shortcuts in tooltips by jess-x · Pull Request #10199 · jupyterlab/jupyterlab · GitHub, both already merged) but you should be able to already configure them manually in 3.0 - just add the shortcuts as in Debugger keyboard shortcuts by mnowacki-b · Pull Request #9154 · jupyterlab/jupyterlab · GitHub into the Advanced Settings Editor.