According to information from twitter, League of Legends will soon introduce a new proprietary MMR system. This change aims to eliminate situations where a player loses 30 points despite winning and only gains 20 LP. Some aspects of this system will already be active at the start of the new gaming season.twit_1742176375199449438
Additionally, Riot Games has plans to further change the system within the year by transitioning to Microsoft's TrueSkill 2. More details about this can be found in the article at (https://www.microsoft.com/en-us/research/uploads/prod/2018/03/trueskill2.pdf).