If you have spent 20-30 minutes of your time holding onto pod install and yet it seems to stuck forever (Possibly installed firebase dependencies then running same project on different machine). Then there are other workaround to it.
Clean cache and pub get your dependencies
flutter clean
flutter pub get
Navigate to your ios folder from the terminal
cd ios
Remove Trunk
pod repo remove trunk
If your current installation is in Intel Chipped Mac run the code below
pod install --repo-update
If your installation is in M1 chip device install ffi first
sudo arch -x86_64 gem install ffi
Then update POD
arch -x86_64 pod install --repo-update
Now clean and fetch dependencies
flutter clean
flutter pub get
If you encountered an error similar to like below
[!] CocoaPods could not find compatible versions for pod "cloud_firestore":
In Podfile:
cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`)
Specs satisfying the `cloud_firestore (from `.symlinks/plugins/cloud_firestore/ios`)` dependency were found, but they required a higher minimum deployment target.
[!] Automatically assigning platform `iOS` with version `9.0` on target `Runner` because no platform was specified. Please specify a platform for this target in your Podfile. See `https://guides.cocoapods.org/syntax/podfile.html#platform`.
Then go to podfile, uncomment platmform:ios line and update it
platform :ios, '12.0'
Now re-run the command
arch -x86_64 pod install --repo-update
Don't Forget to clean pub caches with flutter clean