Princess and HAL just announced the cancellation of north and southbound Alaska cruises, with HAL keeping Seattle round-trip cruises open (for now) while they try to work out the Canada port requirement. Other cruises will be sure to follow with their own cancellations. If you’re affected by a cancellation, contact your TA or the cruise line to discuss your options.
What has not been canceled are small ship adventure cruising, like Uncruise. Another option if you’re devastated about losing your cruise (again?!?) is a land or rail package. Fly into Anchorage or Fairbanks and see Denali and more with no Canada requirement to worry about. Ask me for more info.