if you apply for h1 visa, will your b1/b2 visa automatically cancelled by immigration?

So long as the consular officer has no reason to cancel out the B-1/B-2 visa, they can place an H-1B visa in the same passport. Upon entry, make sure to present the visa that is appropriate for the specific entry. Check your I-94 as soon as the passport is handed back to make sure the correct visa type is listed. You can only be in the USA on one type of visa at a time.