Valve has made an announcement clarifying the status of bans it issued to several proffesional Counter Strike: Global Offensive players in January 2015. As detailed on Counter-Strike blog, the announcement clarified that the ban issued to players who took part in match-fixing are permanant.
“Back in January and early February 2015 we took action after we discovered that a small number of professional CS:GO players were engaged in match-fixing. Our decision was to ban these players indefinitely from involvement in Valve-sponsored events,” Valve wrote in a CS:GO blog post.

“To clarify, the bans for these players are permanent, and players proven to have taken part in match-fixing will be permanently banned.”

“As the scene grows, it’s an unfortunate reality that some individuals will seek opportunities to take advantage of their fans,” the statement says.

“We will continue to take whatever action we think is necessary to protect the entertainment value created by professional Counter-Strike, including, on occasion, terminating our relationship with individuals who have demonstrated a willingness to exploit their fans’ faith in the integrity of the sport.”