“In front of” and “across from” can mean the same thing. I would say “in front of” has the added nuance of possibly meaning directly in front of somewhere/something. If we are speaking about where a location is in relation to another, I would say “across from” and “in front of” have relatively the same meaning. Ex: The bank is across from the school. Ex: The bank is in front of the school. If a person is giving their location in relation to a landmark, then I’d say “across from” invokes a sense of being a greater distance away than “in front of”. Ex: I’m in front of the bank. The person can be directly at the door of the bank. Ex: I’m across from the bank. The person could be on the other side of the street. Just a warning: I’m a native English speaker, so my input isn’t based on having taught English to anyone.