There was no cameo, sorry.

The Skrull at the end... Possibly showing that Sentient World Observation Response Department will be making an appearance. Monica being Spectrum would be a nice addition.

It was white vision. Visions actor hyped up the cameo to be himself

@Tsuki Noke why would anyone be excited for that? I think it was the skrull.

The cameo was Paul Bettany as White Vision.