Thank you for your answer. I'm a student and Convention refugee in Toronto. I used to live Usa. I was student there. I have a lot friends there. I just wanna visit my friends and my school. I got invitation letter from my friend who is US citizen, But I'm afraid to apply with Refugee travel document because I don't have PR card yet. Do you have any suggestions for me?
It is up to the US. If you have a steady job, savings or property, etc will likely make it easier. Not sure if you remained in the US legally for the whole time you lived there but that will have an impact on the approval. Each case is so individual. You will have to apply and see.