Remove list UICollectionView cell separators

You can hide the separator by changing property showsSeparators of UICollectionLayoutListConfiguration (you probably pass UICollectionLayoutListConfiguration to your collectionView.collectionViewLayout when configuring your collection view layout).

Example usage:

let provider = {(_: Int, layoutEnv: NSCollectionLayoutEnvironment) -> NSCollectionLayoutSection? in
  var configuration = UICollectionLayoutListConfiguration(appearance: .grouped)
  configuration.showsSeparators = false // <----- hide separators
  return .list(using: configuration, layoutEnvironment: layoutEnv)
}
collectionView.collectionViewLayout = UICollectionViewCompositionalLayout(sectionProvider: provider)