A server (500), a client device (502) and methods therein, for handling cached content resources. When receiving (5:3) a request from the client device (502) in a downloading session, the server (500) identifies (5:4) a set of caches (504, 506) that can be accessed by the client device (502). The server (500) then sends (5:6) a cache map to the client device (502) indicating that a first content resource is stored in a first cache (504) of the identified set of caches and a second content resource is stored in a second cache (506) of the identified set of caches. Thereby, the server (500) is able to adapt the cache map depending on which caches can be accessed by the client device (502), to ensure that the client device (502) can retrieve the content resources in an efficient manner.