I tried my best to keep this semi-realistic. Some parts might be far-fetched, but I think this timeline works fairly well.

-1939: The 2nd World War begins with the combined Soviet-German invasion of Poland. Britain and France condemn the invasion and gear up for war with Germany. Unlike in our timeline, they cut off communications with the USSR and politically isolate them.

-1940: After intense negotiations with Germany, Spain joins the Axis Powers. They assist in the Battle of France, invading from the south. Tanks are used to break the siege at Dunkirk, turning the evacuation effort into a massacre of French and British troops.

1941: The air war over Britain remains a stalemate between the Axis and Britain. Germany invades the Soviet Union in a surprise attack. Japan attacks the US base of Pearl Harbor. The US declares war on Japan; in turn, Germany declares war on the US. The US maintains its allies' policy of isolating the Soviet Union, fearful of communist influence on their mainland.

1942: An attempt by British and American forces to open a new front in North Africa ends in disaster. They are driven back by a combined force of Vichy French, Italian, German, and Spanish troops. On the other side of the globe, the US, Australia, and New Zealand slowly push Japan out of its island holdings.

1943: Following another round of negotiations, Turkey joins the Axis Powers along with Finland. While their military power is limited, their ability to block the Soviet Union's access to warm water ports proves effective. Without the Lend-Lease Act to aid them, and cut off from outside supplies, the Soviet counterattack stalls outside of Stalingrad.

1944: The Eastern Front becomes a brutal slog as Soviet troops attempt to drive the Axis from their borders, barely gaining much land from the immense losses that both sides take. Japan's defeat is on the horizon as the Battle of Peleliu begins. Quietly, the US and Germany agree to cease hostilities, abandoning their supposed allies to their fates.

1945: President Truman rejects the plan to use atomic bombs on Japan. Instead, Operation Downfall is approved and commenced. The largest naval operation in history begins as American and ANZAC forces invade Japan. The fighting is as brutal as the Eastern Front, with Japanese soldiers and armed civilians battling to the death for every inch of land.

1946: The slow drive to Poland's eastern border finally runs out of steam. The Axis Powers and the Soviet Union end up deadlocked in a back-and-forth conflict in Eastern Europe. Unable to defeat each other, and facing greater issues, Britain and Germany agree to a ceasefire. Britain is independent of Axis rule but becomes isolated from fascist Western Europe.

1947: Rounds of peace talks finally result in a ceasefire between the Axis and Soviet Union. Both sides are aware that they are merely delaying the war and buying time to regain their strength. Their shared border becomes a demilitarized zone.

1948: After years of fighting and an unimaginable death toll, Japan unconditionally surrenders. Emperor Hirohito and numerous other Imperial Japanese officials are executed by a provisional government managed by the US, Australia, and New Zealand.

1949: Mao Zedong's communist forces attack Chiang Kai-Shek's nationalist army. However, without Soviet aid and equipment, they are eventually defeated by the Western-backed Nationalists. Mao and his followers flee to Taiwan, where they set up a communist government and declare themselves to be the true rulers of China.

1950: A "Brown Scare" emerges in the weakened US. Dozens of government officials are accused of being fascist spies, fueled by revelations of Third Reich agents stealing military secrets from the US.

1951-1952: Greece becomes a battleground between fascist and communist paramilitary groups. Recognizing their failure to win over China, the Soviet Union decides to covertly assist communist forces there. In turn, Germany provides aid to its fascist Greek allies. This fascist-communist feud becomes a definitive trait of the growing German-Soviet Cold War.

1953: Joseph Stalin dies. Nikita Khrushchev assumes power as premier. His de-Stalinization policy decries the purges and death camps of Stalin, throwing him under the bus as one of the main reasons why the Soviet Union could not defeat Germany.

1954: A US spy-plane is shot down over German territory, souring relations between the two nations.

1955: The US and USSR enter secret negotiations to cooperate in the event of a war with the German Third Reich. Adolf Hitler dies and is succeeded as Chancellor by Reinhard Heydrich, a fanatical anti-communist and "anti-degeneracy" party member.

1956-1959: Indochina/Vietnam is divided between its Vichy-controlled fascist south and Soviet-controlled communist north. For several years, the two sides wage a proxy war until the country is unified under Ho Chi Minh's communist government.

1960-1961: Two ceasefire violations nearly bring German and the USSR to war. Italy crumbles under communist-led revolts in their African territories. Even with German help, Italy's costly foreign wars prove to be its undoing. Its citizens overthrow Mussolini's government. Turkey attempts to fill the power vacuum left by Italy.

1962: The third and final ceasefire violation occurs. Soviet troops mass along the demilitarized zone and charge into German territory. The Cold War between fascism and communism goes hot. Germany and the Soviet Union enter an all-out war for control of the continent.