Working storage section is the part of data divsion where you declare your variables you are using in your program.

But Linkage section is the part of data division which is used to 1) Receive Parameters passed from other Cobol program (Calling program).

2) It's used to accept the Paramaters passed from the JCL to the COBOL program.

In working storage section we declare variables which is used in the same program.

Linkage section is used to pass the variables from one program to another or we can pass variables from jcl to cobol program.Mostly it is used for subprograms which is called by main program.  

(1) WORKING STORAGE SECTION is used to declare internal data items that is used in the same program.

(2) LINKAGE SECTION is used to declare data items that we want to share with other program.