If you had a valid US visa, you can use it alongside your RTD, or if you had a past visa, you can use it in an interview to obtain a new U.S visa for your RTD. You can also use it to prove your past travel history.
https://www.cbc.ca/news/politics/canada-rudcing-temporary-residents-budget-9.6966217
Quoted from here. Backlog will be cleared. People who applied for PR might get it sooner than they expect. People who applied for asylum after staying in Canada for one year will be rejected automatically...