Isus.rar -

To give you the exact "feature" or information you need, could you tell me:

are you trying to do with it? (e.g., scan it for safety, extract its contents, know what it belongs to)? isus.rar

did you find "isus.rar" (e.g., inside a software folder, email attachment)? To give you the exact "feature" or information

If this file was unexpected, downloaded from an untrusted source, or arrived via email, it is highly recommended to scan it with an antivirus program before opening it. scan it for safety

You will need archive software like WinRAR or 7-Zip to look at the contents of a .rar file.

Here is what I can tell you about managing a .rar file like "isus.rar":

"ISUS" sometimes refers to "InstallShield Update Service."