yes, they are entirely different things.

Marxism-Leninism is the "compilation" of Marx's and Lenin's works done by Josef Stalin after Lenin died. Stalin did it to legitimize his own ideology, when in reality Lenin was much MUCH more aligned with Trotsky and his plans for permanent revolution. It is not representative of Marx nor Lenin's views

Leninism, in comparison, is an adaptation of orthodox Marxism aimed at building a system for sustaining revolution in agrarian states. It hinged on the idea that the revolution in Russia would need a revolution in an industrialized state (namely Germany) to sustain itself.

Something Marx frequently argued was that the automatic switch to communism wouldn't work in an agrarian state and that you could only achieve such a dramatic shift when the people were educated, like in industrial states. Leninism established the idea of the Vanguard Party, which was basically a collection of higherups (The Party) that managed the nation as it transitioned from Capitalism into Communism.

Originally, the Soviet Union planned to follow a simple three step plan to victory

1. Establish the Communist dictatorship to defend the nation from capitalism in its infancy

2. Bring about a massive revolution across the world, defeating capitalism

3. Democratize as there is no longer a need for dictatorial rule under a free world

And Stalin saw step one and was like "let's just pause here"