It can be anything! An apex, subdomain, or even a URL.

Results forwww.infra.mars.trendmicro.com

Logged At	Not Before	Not After	Common Name	Matching Identities	Issuer Name
2023-11-22T08:19:13.517	2023-11-22T08:19:13	2024-12-21T08:19:12	infra.mars.trendmicro.com	www.infra.mars.trendmicro.com	C=US, O="Entrust, Inc.", OU=See www.entrust.net/legal-terms, OU="(c) 2012 Entrust, Inc. - for authorized use only", CN=Entrust Certification Authority - L1K
2023-11-17T06:59:12.124	2023-11-17T06:59:11	2024-12-16T06:59:10	infra.mars.trendmicro.com	www.infra.mars.trendmicro.com	C=US, O="Entrust, Inc.", OU=See www.entrust.net/legal-terms, OU="(c) 2012 Entrust, Inc. - for authorized use only", CN=Entrust Certification Authority - L1K