IB is "near" and i would like to know how the speedrun are going to be listed.

The older run are going to be freezed or will they just be combined ?

or another viewAll leader board or something ?

With the release of Iceborne, a new link will be made (most likely mhwpcib).

World runs will still be runable, however you need to make sure you're on World patch, not Iceborne patch. Any and all Iceborne content will be uploaded to the new link.

Older runs will still be listed under the mhwpc link, so they'll still be there.

With Iceborne patch though, you can still do World quests, it will just be listed under the Iceborne link.

An update on this, here's the new link: https://www.speedrun.com/mhwibpc/

If you do not own Iceborne, you can still upload to World speedruns. But if you have the Iceborne expansion, you MUST upload to the new link.

With the introduction to Iceborne, the monsters will act differently, however we can't do much about that. As for now it's unknown if it will be faster or slower for speedruns.

Best of luck in future speedruns!