It depends. If you are charging your roommate rent in order to make a profit, then you would enter it as rental income.
However, if you only take rent from your roommate to cover the total rent you have to pay, then you would not include this income on your tax return. The CRA would consider it a “cost sharing arrangement”. You can read more on this CRA webpage: https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/rental-income/renting-below-fair-market-value.html
If you have TurboTax Live Assist & Review, here is how to talk to a Tax Expert: https://turbotax.community.intuit.ca/community/navigating-turbotax/help/i-m-using-turbotax-live-assist-review-how-do-i-talk-to-a-tax-expert/00/873764