Five things to know: 1. CVS is expected to try to convince wary investors and a federal judge the transaction will lower healthcare costs for consumers. 2. The federal judge in charge of the hearings, U.S. District Judge Richard Leon, will consider whether the Justice Department adequately alleviated any antitrust concerns in its 2018 settlement with CVS and Aetna. 3. Under the settlement, Aetna agreed to spin off its Medicare Part D drug business to WellCare Health Plans, a deal that has since closed. 4. While judges normally sign off on settlements from the Justice Department without a hitch, Mr. Leon took issue with the DOJ's agreement. During the trial, he will hear from six witnesses, including three that oppose the merger and three CVS-selected proponents of the deal, including Aetna and CVS executives, according to The Wall Street Journal. 5. Despite the hold up in court, CVS and Aetna are carrying on with their merger, which closed in late 2018.