It depends on where you are legally resident for tax purposes.
If you remain a Canadian resident (for instance, you commute across the border, you worked in the US for a short period, you live in the US but still own property in Canada with the expectation of returning, or have other ties to Canada), then you report your worldwide income on your Canadian return, but you claim the foreign tax credit for US taxes paid on your US income.
In the US, if you are a temporary resident or commuter, you report on your US return only your US income. If you are classified as a resident for tax purposes, then you would report your full worldwide income, and claim a credit for taxes paid to Canada on your Canadian income.
As the residency rules can be complicated, you may want to consult a professional.