It worked for me, hope you too.
*Note: I have used auto layout in Nib, remember add top and bottom contraints for subviews in contentView
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let cell = YourCollectionViewCell.instantiateFromNib()
cell.frame.size.width = collectionView.frame.width
cell.data = viewModel.data[indexPath.item]
let resizing = cell.systemLayoutSizeFitting(UILayoutFittingCompressedSize, withHorizontalFittingPriority: UILayoutPriority.required, verticalFittingPriority: UILayoutPriority.fittingSizeLevel)
return resizing
}