As per CRA (Canada Revenue Agency),
The CERB you receive will be treated in the same way as your total income that entitled you to the CERB. This total income is your total income for 2019 or the 12-month period prior to the date of your application.
Therefore, if your total income that entitled you to the CERB is exempt from income tax under section 87 of the Indian Act, your CERB will also be exempt.
If your total income that entitled you to the CERB is partially exempt from tax, your CERB will also be partially exempt. The CERB will be treated as exempt in the same proportion as the total income of the period that is more advantageous to you.
For full information view link below:
https://www.canada.ca/en/revenue-agency/services/indigenous-peoples.html
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