The first time fans were shown a glimpse of Thanos was after the credits in the first Avengers movie back in 2012. Back then the general movie going audience had no idea who the mysterious purple giant was. Then came Guardians of The Galaxy in 2014 and fans got a bit more of an idea who he was through his interactions with ‘Ronan The Accuser’.
In Avengers, the mad titan was played by actor Damion Poitoer. It was then announced that Josh Brolin would be officially playing the role of Thanos going forward. In Guardians of The Galaxy, Thanos was created using CGI and motion capture similair to how Mark Ruffalo plays the role of The Hulk. Brolin also played Thanos in the end credits scene of Avengers: Age of Ultron, as seen below…
Now Ironhead Studios who created and designed Thanos’ armour for the Marvel Cinematic Universe (MCU) have released a picture of what Thanos would look like if the studio went with practical effects instead of CGI…
In order for Thanos to be the right size and to keep in line with his size in previous movies, a motion capture method would fit much better. Marvel and The Russo Brothers will most likely stick to the way that Thanos looked in Guardians of The Galaxy and Avengers: Age of Ultron because there isn’t anything wrong with the way he looked in those movies at all. He looked menacing and threatening and like he definitely looked like something that will take all the heroes in the MCU combined to defeat.
While it hasn’t been confirmed, at one point there were rumours going around that Thanos could make an appearance in Thor: Ragnarok. Kevin Feige has said that Thor 3 would impact everything that came after it in the MCU, this combined with the fact that Thor and Bruce Banner will be travelling around multiple realms, it’s not such a stretch to think that Thanos could appear somewhere.
We may see Thanos in Thor: Ragnarok which will be released on November 3rd 2017 and I think its a safe bet that Thanos will be showing up in Avengers: Infinity War Part 1 which hits theatres on May 4th 2018.
Source: Comic Book Movie