The following packages have unmet dependencies

Hallo,
would you guys help me?

i install Debian buster but using repo stretch.
i want to deploy pxc 5.6
but, when i install package,
i get error :

The following packages have unmet dependencies:
percona-xtrabackup : Depends: libcurl3 (>= 7.16.3) but it is not installable
percona-xtradb-cluster-server-5.6 : Depends: iproute but it is not installable
E: Unable to correct problems, you have held broken packages.

what should i do ?
would you like to help me please?