If used in a sentence with an event that may happen in the future, and even if you are talking about an event is present as future simple tense is used (in the sentence if clause) instead of future tense.
If used in conditional sentences To events that may occur in the future. Despite talking about future events is given, then the present simple tense (in the sentence if clause) represent the future tense.
Use if in conditional sentences to an event that may occur in the future. Even talking about events that the future way is to use a present simple tense (in a sentence if clause) instead of future tense.