This article has spoilers for the second episode of The Falcon & The Winter Soldier. Please refrain from scrolling down if you haven't caught up yet. 

The Marvel Cinematic Universe has mostly played safe with its storylines so far. But given that its heroes routinely go to war, one of the things it does talk about is PTSD. It covered the subject in Iron Man 3 and later dived deeply into the concepts of loss and grief with WandaVision.

Iron Man 3 PTSD
Source: Polygon

With The Falcon & The Winter Soldier, however, the MCU has been actively dealing with PTSD faced by real soldiers. Also, given the recent state of affairs in the United States, the show has also been showing the rampant racial discrimination that still exists on its streets. 

In order to effectively portray some semblance of reality, the show has dived into Captain America's lore from the comics and introduced Isaiah Bradley, the Black Captain America. 

Source: Sportskeeda

At the end of the second episode, Bucky tells Sam that they have to go meet a guy who knows a thing or two about the super-soldier serum. 

That man turns out to be an old guy called Isaiah, a super-soldier like Steve and Bucky, who fought during the Korean war and took Bucky's metal arm. You would assume that having that kind of power would get him a good life but instead, it is revealed that he had been put into prison for 30 years and experiments were run on him.  

Source: Polygon

No points for guessing why he was treated differently than the blonde-haired, blue-eyed Steve Rogers. 

They put my ass in jail for 30 years. People running tests, taking my blood, coming into my cell.

                    - Isaiah Bradley

While the show will surely reveal more as the episodes keep releasing but the comics will give you more of an idea about what exactly went down with Isaiah. 

In the comics, during World War II, the US government wanted more super-soldiers like Steve. So they started experimenting on black soldiers. German eugenicist scientist Dr Wilfred Nagle experimented on 300 black soldiers, 295 of whom died.

Source: EW

The remaining soldiers were killed along with their families and close friends in order to cover up this inhuman torture by the government. 

Bradley was one of the few soldiers who survived and gained abilities that allowed him to take the mantle of Captain America and led successful missions all across the world. 

However, when he returned home, the American justice system, as racist as it was and still is, sentenced Bradley to prison for stealing the shield. Isaiah was eventually pardoned when JFK was elected to power but by then his mental health had seriously deteriorated. 

Now, if you are thinking 'Thank God, at least that was fictional', I've some bad news for you. It's not entirely fictional. Creators, Robert Morales, artist Kyle Baker, and editor Axel Alonso used the very real incident of Tuskeegee Syphilis Study in the 2004 limited series Truth: Red, White, and Black.

Now, if you are thinking 'Thank God, at least that was fictional', I've some bad news for you. It's not entirely fictional. Creator Robert Morales, artist Kyle Baker, and editor Axel Alonso used the very real incident of Tuskeegee Syphilis Study in the 2004 limited series Truth: Red, White, and Black.

The Tuskegee Study involved a 40-year-long, Public Health Service-conducted study started with 600 Black men from poverty-stricken areas of Alabama. The government promised them free treatment and ensured that the study would only last 6 months. 

Source: NPR

However, according to Gamesradar, 399 of them were never treated for undiagnosed Syphillis which the CDC used to extend the study for over 40 years from 1932 to 1972. This meant hundreds of Black men suffered from the horrible effects of syphilis. 

Now, coming back to Bradley; after being released from prison, he became an underground hero to the black community, despite the Avengers or the other heroes never having heard of him. But black heroes like Luke Cage, Monica Rambeau among others, hold him in high esteem. 

Source: Polygon

Isaiah Bradley's story, however, ends tragically due to the side effects of the improper serum injected into him, which eventually deteriorates his mind to an extent that he gets a condition similar to Alzheimer's. It is later revealed that the super-soldier experimentation that he went through was part of the programme that gave Weapon X Wolverine his adamantium claws.

Isaiah eventually passes on his powers through his DNA to his grandson, Eli, who goes on to become a member of the Young Avengers. As far as the MCU is concerned, it will be interesting to see how Isaiah's story infolds here. 

Source: comicbook

That said, MCU has been introducing members of the Young Avengers, like Wiccan and Speed (WandaVision), Kate Bishop (Endgame) and now Eli Bradley. So, that will be something to look forward to.