回複：485 pending - travel to Canada for new H1B visa

If you get H1B visa and come back, there is no adverse effect to your pending 485. But there is some slight risks:

1. You could be checked applying for H1B. While waiting for the check, you shouldn't reenter US, otherwise your H1B might be denied.

2. There is a very slim chance your H1B could be denied for whatever reason.

A safer way is to get Advance Parole first, then go to Canada for H1B visa.