Recent set photos for Infinity War seem to suggest that Thanos' right-hand man and leader of the Black Order Corvus Glaive could be making an appearance. Corvus made his first comic appearance during 2013's Infinity crossover and, if Marvel are willing to borrow from that story, it stands to reason that they might copy Thanos' defeat too.
Infinity also introduced Thane. He was a young man who worked as a healer in a remote Inhuman village. However, it turned out he was also secretly Thanos' son and, after being exposed to the terrigen mists, he used his new powers to trap his father in stasis.
Adapting this for Infinity War could make for an interesting plot as Earth's heroes race against the Black Order to find the one being capable of stopping Thanos. Thane's Inhuman roots would also finally allow Marvel to give that group a strong tie to the MCU.
It could also set up the film's currently untitled sequel. Like in the comics, Thane could become corrupted by his powers and turn to villainy, maybe even taking the Infinity Gauntlet for himself as a final cliffhanger in Infinity War. Then the sequel could be about the Avengers and the Guardians of the Galaxy trying to stop the villain they helped create.