It appears that the end of a partnership will be the outcome of the dispute between WM and CVS over the high reimbursement rates in CVS Caremark's network of PBM.
Anyone with CVS-administered d--g benefits and Medicaid enrollees with CVS d--g coverage will be affected if the split happens, CVS said Tuesday. That means pr-scrip-ions filled at a Walmart pharmacy might not be eligible for coverage by their d--g plans.
https://www.cnbc.com/2019/01/15/walmart-pharmacies-likely-to-leave-cvs-network-because-of-pricing-dispute.html