Medium Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Conflict Airborne Conflict; Inflight Event / Encounter Other / Unknown
Flight Crew FLC Overrode Automation; Flight Crew Took Evasive Action
Environment - Non Weather Related; Human Factors
Level at 4;000 feet we were on a heading to intercept final into XXL into ZZZ. ATC turned us left to avoid traffic. We had traffic on our TCAS to the left. We tried to verify if left was actually what ATC wanted and they verified yes. Upon taking the new heading; I saw Aircraft Y out my side of the aircraft maneuvering in circles. It was doing a climbing left 360. Just as Aircraft Y was turning our direction; the movement of the aircraft seemed to stop in my windscreen. As we all know; that indicates it was coming right at us. I turned off the autopilot and turn our aircraft to the right and almost braced for impact. The plane was less than 300 yards away. We never received an RA (Resolution Advisory); but that was close. We need to be hyper vigilant coming into ZZZ. These near misses are getting out of control. This was the third one in two days for me alone. ATC can help; but eyes out the windscreen and no heads down work coming into ZZZ. Period. Be careful everyone!
Air carrier Captain reported experiencing an airborne conflict on approach to landing that required immediate evasive action to avert a collision.