Sniper Elite had Steam trading card support added on 8 October 2014. There are 6 cards in the series, and you'll receive 3 cards at random for purchasing and playing the game.
The other games in the series, Sniper Elite V2 (including its remaster), Sniper Elite 3, Sniper Elite 4 and Sniper Elite 5 also have trading card support.
Trading Cards
Foil Cards
Badges
Booster Pack
Emoticons
Profile Backgrounds