European markets commenced June with caution on Monday, marked by modest declines, as the Stoxx 50 decreased by 0.3% and the Stoxx 600 edged down 0.1%. This market sentiment was largely influenced by renewed trade tensions following U.S. President Trump's announcement of plans to increase tariffs on imported steel and aluminum to 50%, heightening global trade conflict concerns. In response, the EU hinted at possible retaliatory measures, affecting the auto sector significantly. Stellantis fell by 5%, while shares of Mercedes, BMW, and Volkswagen decreased by up to 2.7%. Additionally, sectors such as luxury and media experienced declines. Conversely, oil stocks rose by 1.4%, attributed to a surge in crude prices after OPEC+ announced a smaller-than-anticipated output increase. In the defense sector, Babcock and QinetiQ experienced gains following news of the UK’s intentions to expand its nuclear submarine fleet. Meanwhile, Sanofi's shares dropped by 1.8% after the company declared a $9.1 billion acquisition of Blueprint Medicines. On the economic data front, the manufacturing PMI indicated signs of stabilization across the Eurozone, though Germany continued to show weakness. Investors are now closely monitoring the European Central Bank's anticipated decision regarding a rate cut on Thursday.