SPOILERS for AVENGERS: ENDGAME. Be warned. As the epic finale of The Infinity Saga, AVENGERS: ENDGAME brought together just about all the major players of the Marvel Cinematic Universe as they fought to save the entire galaxy from Thanos (Josh Brolin), but that doesn't mean that the film didn't include a few cameos which might have passed your notice.
London-based VFX company Cinesite has released a VFX breakdown of their work on AVENGERS: ENDGAME, which also reveals a rather sneaky cameo from Arnim Zola (Toby Jones), the HYDRA scientist who appeared in both CAPTAIN AMERICA: THE FIRST AVENGER and CAPTAIN AMERICA: THE WINTER SOLDIER. The sequence in question can be seen at 00:40 into the video. When Tony Stark (Robert Downey Jr.) traveled back in time to S.H.I.E.L.D. headquarters in 1970, a computer monitor with Zola's face on it can be seen far in the background. At this point in the Marvel Cinematic Universe, Zola was still alive, but it's clear that he was already working to transfer his consciousness into a computer before his death in 1972.
AVENGERS: ENDGAME is now available on Digital as well as DVD/Blu-ray/4K Ultra HD.