The Medicare-X Choice Act of 2025 creates a new public health insurance option available through existing health insurance marketplaces starting in 2028 for individuals and small businesses not eligible for Medicare, funded with $2 billion for establishment and operations through 2036. The plan will offer silver and gold coverage levels with no cost-sharing for primary care, use Medicare-negotiated reimbursement rates for providers, and eventually require all Medicare and Medicaid providers to accept it. The bill also expands tax credits for health insurance by removing income caps, funds a $10 billion reinsurance program to lower premiums, and directs integration of health care with social services like food assistance and housing. Additionally, it authorizes grants for "accountable communities for health" models, eliminates restrictions on Medicare drug price negotiation, and allocates $150 million for antitrust enforcement to increase competition in health care markets.