The Blues were hopeful of sealing a deal to re-sign Ake but the 27-year-old will now remain at City after the two clubs failed to reach an agreement over a transfer fee.
It forces Chelsea to consider other options and they are set to revisit a move for Kounde as Tuchel Tuchel bids to rebuild his defence this summer.
Chelsea are closing in on a £33million deal to sign Kalidou Koulibaly from Napoli and they are also interested in Paris Saint-Germain defender Presnel Kimpembe.
Kounde missed out on a move to Stamford Bridge last summer when Sevilla refused to sell him and Chelsea were not willing to meet his £68.4m release clause.
The France international was relegated from a priority signing to a back-up option by new co-owner Todd Boehly as he instead targeted moves for Matthijs De Ligt, Ake and Koulibaly.
De Ligt has made it clear he wants to join Bayern Munich from Juventus and, with Ake now set to stay at City, Chelsea are set to go back in for Kounde.
But they face a fight with Barcelona for the 23-year-old. Reports in Spain claim Barcelona have agreed personal terms with Kounde but the Catalan club are yet to negotiate a transfer fee with Sevilla.
It is unclear whether Barcelona can afford Kounde given their financial problems but Chelsea will need to act swiftly.
Chelsea need to rebuild their defence this summer after losing Antonio Rudiger and Andreas Christensen. They could also go into the new season without Cesar Azpilicueta, who has agreed terms on a two-year deal to join Barcelona and is waiting for the Catalan club to stump up a £7m transfer fee to sign him.
Should Azpilicueta depart, Chelsea will target a move to sign a new wing-back and they are interested in Jonathan Clauss from Lens.