A couple things might be happening. For some reason is your Notebook “Not Trusted?” This will stop the Plotly javascript from rendering anything below.
Another possibility is that you don’t have the Plotly extension installed for Jupyter Lab. In Lab, as compared to Notebooks, there are a lot more restrictions on what javascript can execute, so packages need to have extensions installed in order to display anything beneath the cell.
Look for the plotly-extension with
jupyter labextension list
and install it if missing with: jupyter labextension install jupyterlab-plotly