Wanda Vision is part of the Marvel MCU. its a series on Wanda Maximoff aka the Scarlet Witch. it picks up right after the Avengers Endgame movie......though from the series thus far you would not know that. however, there bits and pieces being shown that suggests this. the series so far opens up like a tv sitcom in the 50's in the first episode. the second, im guessing was more like 60's. and the 3rd episode was more like the 70's.
in each episode you begin to see that something is not quite right in Wanda's world. it's a very interesting concept. there are slowly peeling the layers back revealing exactly what is really going on......but we are not there just yet.
i won't say anymore on my theories as it might be spoilers for some. check it out though.