Pfizer and Mylan say the new company should have synergies of approximately $1 billion annually by 2023. Mergers and acquisitions frequently lead to layoffs. Synergies is what you get when you eliminate redundancies in your efforts to cut costs. Jobs will be cut on both sides no doubt, but the side that gets cut in bigger numbers may be the side that cost the company more than the other.
@SPnDJHF-7Bjsu makes a good point.