When building the workspace throws a warning:
Target Pods - {AppName} product Pods_{AppName} cannot link framework Foundation.framework
This started after updating to Xcode 9.4. I updated CocoaPods to the latest version, v1.5.3, but it didn’t resolve the warning.

This is due to using the new build system in Xcode. The issue has not been resolved in the latest version of CocoaPods yet, v1.5.3 as of writing this.
For now, you can resolve the warning by adding this
post_installaction to your pod file:After updating your pod file run
pod installagain.Source: CocoaPods: Cannot link framework Xcode warning