First Military Conflict
North Korea invaded South Korea on June 25, 1950. The North Korean troops outnumbered the South Korean troops by 89,000 to 38,000. The troops defending the border were alarmed and taken by surprise. Three days later, the capital of Seoul fell. That was when North Korea began its invasion to take over South Korea, causing the US to help aid the South. The first major clash between North Korea and the US was the Battle of Osan on July 5, 1950. That opening battle resulted in a North Korea victory as the US's concern for the war ahead grew.
The first armed conflict of the Cold War was the Korean War and set the standard for many later conflicts. It's often referred to as the "Forgotten War". It stirred up much tension between countries because of their different views on communism or anticommunism. The Korean War created allies and foes and the UN Security Council had to intervene as well. In a way, the Korean War sparked up the beginning of the Cold War. It was the first test of the Truman Policies, NSC 68, and the newly formed NATO countries as well against a communist aggressor. It not only started the Cold War in Asia but also the French fighting Indo-China War in Vietnam.
Implications :
In brief, the Korean war ignited the flame in the Cold War. Sides were picked and tension increased because of this war. After all, it was the first armed conflict of the Cold War.