It's still unclear whether Sadio Mane will replace Lewandowski but one or two Bayern players if they don't have a big impact because the Bayern team is already very solid on all fronts.
Sadio Mane has reportedly agreed to join Bayern Munich next season. But for Lewandowski there has been no recent news regarding him whether he is still staying at Bayern Munich or actually leaving. If Lewandowski still survives it looks like it will be a better collaboration than Mane and Lewandowski in attack.