pass ip 1.2.3.4 .....
will not generate alerts , but Suricata will continue to generate any and all network protocol logs to/from that ip - ex: DNS / SMB / DCERPC / FTP / TLS / HTTP / Fileinfo etc etc
pass ip 1.2.3.4 .....(content:“something”; bypass; sid:123; rev:1;)
will make Suricata not generate any type of logs for that ip.
However you might also want to look at conditional protocol logging: 6.33. Config Rules — Suricata 6.0.11 documentation