Internet Explorer 8 Portable Full [repack] -

Short answer:

Because it is no longer updated, IE8 is highly vulnerable to modern malware, phishing, and exploits. Using a "portable full" version from unofficial sources increases the risk of bundled spyware or viruses. Web Compatibility: internet explorer 8 portable full

Are you trying to run a that requires IE8, or are you doing historical research on browser development? Short answer: Because it is no longer updated,

Released originally in 2009, Internet Explorer 8 (IE8) represented Microsoft’s attempt to modernize its browsing experience with features like Accelerators Web Slices InPrivate browsing you are asking for ransomware.

IE8 has unpatched, publicly known remote code execution vulnerabilities. If you plug a USB drive with a "portable" IE8 into a Windows 10 machine and browse random websites, you are asking for ransomware.