Carl Quintanilla and Jim Cramer covered all of the bases on a historic day for Nvidia: The chipmaker became the first company to achieve a $4 trillion valuation. Hear what Jim had to say about what's ahead for the stock. Also in focus: Apple's Jeff Williams to step down as COO, copper tariffs and what they could mean for Tesla, UnitedHealth and the DOJ, Merck's $10 billion deal to acquire Verona Pharma, President Trump's 200% pharma tariff threat.