What is the international code for the US from Cameroon?

The telephone country code for North America (US, Canada, and several island nations and territories in or near the Caribbean) is +1. The plus sign means "insert your international access prefix here."

The international access prefix from Cameroon is 00, so to call the US, dial

00 + 1 + area code + number.

(To call from the US to Cameroon, dial 011 + 237 + number.)