How did relations between the USSR and Germany change in the 1930s, what is the reason

How did relations between the USSR and Germany change in the 1930s, what is the reason for the last change, what are its consequences for the USSR, Germany and the world as a whole?

In the 20s of the 20th century, trade relations were actively developing between the USSR and Germany, an agreement on military-technical cooperation was signed, that is, the countries were allies. Changes occurred with the coming to power of Hitler, who began to spread the ideas of Nazism, wanted to gain world domination. Since then, many countries began to fear the manifestation of aggression from Germany and created a system of collective security. Germany, on the other hand, unleashed the Second World War, as a result of which the countries were destroyed. This war put an end to the era of colonial possessions, the world has changed dramatically, values ​​have changed.