This year, and perhaps for the future, Halloween will be different. Trick or treating might be an idea of the past. As people struggle with social distancing it is very unlikely many people would allow their children to scamper up walks and ring doorbells awaiting candy. It is also unlikely many people will be answering the doorbell.
Parents can buy candy and distribute to their own children. This is safer and allows for portion control. And the children are more likely to get the candy they like.
Costumes might become less plentiful. Halloween costume parties might be fewer as caused by the need for social distancing.