All players start at 15% cashback in the basic rewards program. As players earn points, open chests, and move up the chest levels, the basic program tops out at 25%.
Through Weekly Challenges, players can get an additional 40% rakeback. However, these only become available once the player reaches the Silver tier, which means that the maximum rakeback at the Blue and Bronze levels remains 15% and 16%, respectively.
There is less detail about how the Weekly Poker Challenges play out with individual users. According to PokerStars, most players will see a 40% cashback from the Challenges, but some players will only get 10% cashback. That difference will be based on player profiles, but there is limited data about how that will be assessed.
That means that the maximum reward a player can get is 65% cashback at the highest levels. That is made up of a 25% return from the Black level of the basic volume-based program, plus up to 40% from the Weekly Poker Challenges for a total of 65%. For those only offered 10% in Challenges, that will still amount to 35% rakeback each month—though it remains to be seen if challenges are reasonably attainable or not.