The player's efforts of the new season is not necessary or needed when giving out award of a previous season to deserving players. It is the achievements and performances of the players in the recently concluded season that are carefully and critically analyse to determine who will win the Ballon d'Or. So Dembele don't need to win any trophy this season or put in any other special performances to increase his chances of winning the Ballon d'Or in the current season.
This discussion about the Balon d’Or rightful winner is getting evident more and more that Dembele is the best person for that award. He has proven himself worthy that he’s most deserving of being given that award. With PSG, in one calendar year, he has won five trophies with them and also reached the FIFA Club World Cup final and finished as runner up. The super cup final I think is inclusive to determine the award and he just won that yesterday also. I am still seeing more and more reasons why he shouldn’t be denied this award and if he is, then the award is not based on individual performance and achievements again, and maybe preference of a particular player is what decides the winner and that won’t be fair to him.