ld: framework not found Pods
This is usually caused by having the .xcodeproj file open instead of .xcworkspace.
When you run 'pod install' for the first time, it will create an .xcworkspace file, which includes your original .xcodeproj and a Pods project. You'll need to close your .xcodeproj and open the .xcworkspace instead.
This is a common issue when creating a project through Xcode's new project wizard - I often forget that I'm not in a workspace, which is required to get Cocoapods to link correctly.
Xcode 9, 10, 11, 11.5
install https://github.com/CocoaPods/cocoapods-deintegrate
pod deintegratethen
pod install