The US C-corporation (subsidiary) will pay US federal income tax at a rate of 21%, plus applicable State Income Tax on its annual profits
If the income earned is passive in nature, then there will be a small net income inclusion for the Canadian Parent Corporation in respect of the US net passive income earned (i.e. FAPI)
If the profits remain with the US C-corporation, then there is no further Canadian taxation (other than FAPI)
When the US C-corporation pays a dividend to the Canadian Parent Corporation, a 5% dividend withholding tax becomes payable to the IRS. In addition, the Canadian Parent Corporation can claim a tax deduction for the dividends received.
When the Canadian Parent Corporation pays dividends to you, those dividends will be classified as eligible dividends, which have a lower tax rate.