Hextech Gunblade was only purchased on champions who wanted to one-shot enemies. It was not a viable option for almost all champions in the game, so this item's getting removed.

Did riot remove Hextech gunblade?

League of Legends Season 11 has seen a huge change in the game's items. ... And, as a slew of items have been added to the game, so too have they been removed. Classic tools like Frozen Mallet, Hextech Gunblade, and Statik Shiv were all sent to the Shadow Realm during the preseason.

Is Hextech GLP removed?

Item was removed in Patch 10.23.