Well, according to recent reports they are going to have to sell Kanté to be able to afford Havertz, because his club is not moving on the fee.

http://www.eurosport.com/football/transfers/2019-2020/chelsea-willing-to-sell-n-golo-kante-to-raise-kai-havertz-funds-paper-round_sto7779734/story-amp.shtml

Kante out, Havertz in

“ Chelsea are willing to sell N'Golo Kante to raise funds to sign the highly-rated Kai Havertz this summer. The Blues have already confirmed the summer signings of both Hakim Ziyech and Timo Werner but a report from the Times reveals that Chelsea aren't done shopping just yet. Havertz is said to be wanted by Real Madrid, Manchester United, Bayern Munich and Liverpool but Chelsea believe they can pip their rivals to the signing due to a financial advantage. The west London club are willing to sacrifice N'Golo Kante - who has been a long-term target of Zinedine Zidane's Real Madrid - to ensure they have the funds to sign the £90-million rated German wonderkid.

Paper Round's view: N'Golo Kante is a world-class footballer - but this isn't actually the worst idea. The World Cup winner will turn 30 next season and Real Madrid are still willing to pay a huge fee for Kante. The Frenchman hasn't really found his form so far this season under Frank Lampard and there have been question marks over his ability to adapt to the Blues boss' tactical system. Kante's exit would probably mean Chelsea need to sign a new box-to-box midfielder... or find an internal replacement in their squad (Billy Gilmour or Ruben Loftus-Cheek?). The deal could be worth it if it ends up with Chelsea beating their big-name rivals to the signing of Havertz - who has lit the Bundesliga up over the past two seasons.”

And I’m not really big on spending 90 million for Havertz who is unproven in the EPL. Kid is very talented, but there is similar talent out there that isn’t as expensive. Whenever we spend big for a player we get burned ..Schrilenko, Torres, Morata, Kepa.

Our focus should be on correcting that back line and getting a GK. We got three good strikers, we got pulisic, Odi, Mount, RLC, Ziyech, Mateo. ...Ampadu, Victor Moses and kenedy will back from loan. So get another winger and a DM

But the focus has to be on that back line and GK...we gave up 60 goals this year .the most in the epl. Just got killed by Bayern Munich and that was with Kanté on the field. We need to focus on what we actually need.