Date: 202103
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Second aircraft: Commercial Fixed Wing
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Workload; Distraction; Communication Breakdown; Situational Awareness
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Took Evasive Action
Contributing factors: Weather; Procedure; Human Factors; Staffing
Primary problem: Human Factors

Narrative: We pushed off the gate and taxied out to spot XX to switch to ground. Upon reaching the spot; we contacted ground a minimum of 6 times and sat for more than 5 minutes before finally getting a response. We had planned for runway XXL but were given XY which was unusual for a northbound departure out of ZZZ. We were told to taxi 1; 2 and to give way to company traffic which was passing right to left on [Taxiway] 1. Once the traffic had passed; we made the left turn onto 1 and I announced to the Captain that I was going heads down to change the runways. I changed the runway on the route page and it did not uplink so I glanced at the iPad for a quick check of the numbers. During that quick look; movement caught my eye out of the rear right window and I turned to see another aircraft quickly approaching the Captain's blind spot on either [Taxiway] 3 or 4. I alerted the Captain of the traffic and he aggressively applied the brakes and stopped the aircraft prior to the intersection. The other aircraft taxied past without noticeably altering its speed and we continued taxing once clear. I am confident that both aircraft would have experienced a fuselage to fuselage collision had we not noticed the traffic at the precise moment that we did.  Ground controllers were busy and weather was in the area. I don't know where the other aircraft came from but we were never given any reference to the traffic or hold short instructions. Additional staff working the ground frequency for that particularly busy bank in ZZZ. Also; make crews aware that when two taxiways intersect at less than a 90 degree angle on the right side; there is a significant blind spot for the captain which makes checking for traffic very difficult.


Second narrative: We were cleared to taxi to runway XX from spot XX via [Taxiways] 1 and 2.  The airport had just reopened after being closed for weather.  Controllers were swamped trying to give clearances and deal with multiple aircraft.  We were not advised of approaching aircraft nor were we issued hold short instructions.  Another aircraft was approaching the [taxiways] 1 and 2 intersection on [Taxiway] 2 while we were approaching on [Taxiway] 1.  They were coming from our right rear at a 45 very fast.  My FO (First Officer) saw him first as he broke into his field of vision he alerted me.  I applied mildly aggressive braking to stop while the other aircraft showed no signs of slowing down.  If I had not been alerted or even alerted 2 seconds later there would have been a collision in the intersection.  It was a dangerous near miss that even after the fact neither ground nor the other aircraft seemed aware of.  I contacted ground and told them it was near miss.Airports are starting to get busy again but I feel controllers and pilots are not as current as we were.  Someone should have caught this before it happened.Ground is going to have to step up their game if airlines are adding flights to ZZZ.  You can't be giving clearances on ground frequency when you are already overloaded.  That's crazy.


Synopsis: Air Carrier flight crew reported a critical ground conflict occurred during taxi out and stated they were not advised by Ground Control of the approaching aircraft.