B737 Captain reported receiving a traffic advisory with traffic that was behind the aircraft and landing on the parallel runway. The flight crew performed a go-around after complying with the resolution advisory.

Narrative

As we were vectored for a visual approach to [Runway] XXR ATC called out Airbus traffic for us that was joining the approach to [Runway] XXL behind us. As we could not maintain visual contact with the traffic behind us ATC told us the Airbus would maintain visual separation with us. We lost sight of the Airbus as we joined our final approach course just slightly ahead of the other traffic. I was hand-flying and was slightly; approximately one dot on the localizer; right of course; north; aware that the Airbus was almost abeam us when they joined the [Runway] XXL course to our left. Soon after we received a TCAS TA. On our MFD (Multi-function Flight Display) the traffic appeared directly under our position 100 ft. below us. Very soon after receiving the TA we received a TCAS RA instructing us to level off. We complied with the RA and subsequently executed a go-around. During the RA go-around my FO (First Officer) stated he briefly had visual contact with the Airbus slightly behind and below our left wing. Had we used the company endorsed policy of selecting TA ONLY mode on the TCAS we may have descended into the conflicting traffic that appeared to have been north of their final approach course.