A few years after the release of Halo 5: Guardians, one of the developers confirmed that a PC port was indeed in Microsoft's plans. However, it was later canceled due to implementation issues.
Halo 5: Guardians was released back in 2017 on Xbox One, essentially becoming a platform exclusive. Only a «stub» in the form of Halo 5: Forge reached PC players a year later. Microsoft denied all rumors about the release of a computer version year after year, until finally developer Tyler Owens said that the port was still in the plans. He said this yesterday on social networks:
I wish but it's never going to happen imo. I think the port that was being considered ran into significant tech hurdles and was scrapped.
Tyler Owens could not provide more details about the situation. At that time, he did not hold a high enough position to be aware of all the details. However, as users suggested, the problem was the frame rate-bound physics. Many console ports of that time faced this drawback — remember at least the PC version of GTA: San Andreas. In any case, Microsoft decided not to invest in the development.
Let us remind you that tomorrow another console exclusive will be released on PC. After 14 years, Rockstar has finally made a computer version of Red Dead Redemption.