Did you receive any T5007 slip? if you have T5007, the amount received is reported as income, however it will be deducted as a deduction at the same time.
Whether Wage loss replacement plan is taxable or not will depend on how the plan is setup. Any wage-loss replacement benefits that you receive are subject to source deductions of income tax. Depending on how plan is setup you may get T4 slip or T4A slip for this benefit which should be entered in the product to calculate your taxes. If you have not received any slip you can contact Sunlife or your employer to get more information about your plan.
Here is link to CRA document that explains how wage loss replacement plans work :