While Shang-Chi's debut in the Marvel Cinematic Universe has been a resounding critical and commercial success at the box office, the post-credit scene at the end of Shang-Chi and the Legend of the Ten Rings effectively locks the character out of one of the more popular storylines in the comics. The MCU is no stranger to deviating from source material; indeed, stories like Civil War are much improved during their page-to-screen transition. But in Shang-Chi's case, the change is so drastic that the narrative in question cannot possibly be adapted.
Shang-Chi's family plays an important role in the comics as well as on film. Shang-Chi was originally the son of Fu Manchu, but Marvel changed that aspect of the hero's backstory when the higher-ups realized that Fu Manchu was a racist and stereotypical portrayal of Asians in comics (and on a more cynical note, the company did not hold the rights to the character). Instead, Shang-Chi's father was Zheng Zu, a powerful sorcerer and Supreme Commander of the Five Weapons Society, known in the 2021 film as the Ten Rings.
Upon defeating his father, Shang-Chi inherits the Five Weapons Society and seeks to reform the organization into a force for good. However, in Shang-Chi vs. the Marvel Universe, he must constantly choose between helping the superhero community of Earth and his family - and their traditional values stipulate that one cannot choose both. Unfortunately, the post-credits scene at the end of the film tells a different story: it's Shang-Chi's sister Xialing who takes control of the Ten Rings, not Shang-Chi himself.
In Shang-Chi vs. the Marvel Universe, Shang-Chi has fought Spider-Man, Captain America, Wolverine, and the Fantastic Four - and all are increasingly suspicious of Shang-Chi's true intentions. In the comics, Shang-Chi's sister fights by his side, but the film version of Xialing is quite antagonistic toward her brother (understandably so, considering that he failed to return for her after he fled their father's compound). Since Xialing controls the Ten Rings, there remains virtually no chance of Shang-Chi fighting each of the major heroes of the MCU as he does in the comics. Perhaps the roles will be reversed and Shang-Chi fights on the side of the Avengers against his sister, and it will be Xialing who is torn between the Ten Rings and her brother.
Shang-Chi's future in the MCU remains a mystery, as does his fate in the comics. Will his loyalty to his family and the Five Weapons Society put him in the crosshairs of the Avengers for good? Only the writing staff and Marvel editorial can say for sure - but whatever the case, Shang-Chi vs the Marvel Universe is a story that can no longer be told in the MCU.