Receiving error in search to compare two fields

Where is the error? (index=paloalto sourcetype="pan:threat" action=allowed severity=critical src_interface="ethernet1/2.110") OR (index=trend sourcetype="deepsecurity-intrusion_prevention") | eval cs23=replace(cs1, "\"", "") | eval match=case("threat:cve" == cs23,"Yes","threat:cve" != cs23,"No") | stats count by match