The skin does not appear

someone knows why they did not give me the skins of studios?
if I look at all the E3 in mixer

If you watched on Mixer for E3, then check ‘Gears of War 4’ > ‘Manage Game’.
You should find a Microsoft Studios Pack available to download or install, which should appear in ‘Store’ > ‘Unopened Pack’ in-game.
It’s MS Studios Lancer.