This code system http://terminology.hl7.org/CodeSystem/benefit-network defines the following codes:

CodeDisplayDefinition
in In NetworkServices rendered by a Network provider
out Out of NetworkServices rendered by a provider who is not in the Network
 <status value="draft"/> <experimental value="false"/> <date value="2023-02-25T11:07:30-07:00"/> <publisher value="Financial Management"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> </contact> <description value="This value set includes a smattering of Network type codes."/> <copyright value="This is an example set."/> <caseSensitive value="true"/> <valueSet value="http://terminology.hl7.org/ValueSet/benefit-network"/> <content value="complete"/> <concept> <code value="in"/> <display value="In Network"/> <definition value="Services rendered by a Network provider"/> </concept> <concept> <code value="out"/> <display value="Out of Network"/> <definition value="Services rendered by a provider who is not in the Network"/> </concept> </CodeSystem>