Overview
A big set of changes is set to hit League of Legends in the coming months, which you can learn about below in their latest video. These changes will roll out largely with Season 3 as League of Legends shifts towards the 15th World Championship in China. These are the main things you need to know:
Xin Zhao visual update (no changes to gameplay) and new epic skin
Base Summoner's Rift map returns (more new ones planned for later)
All vaulted skins will be unvaulted in 25.17 and 25.18
2024 T1 Worlds skins coming in September
Machine Herald Viktor will be released in 25.19 -- all Viktor players with Mastery 5 or above will get it for free
Doom Bots returns in 25.17 with new bots, new boss, new difficulty, and more! New patches will add new content.
WASD control scheme will be added and tested in PBE before being fully rolled out
Patch 25.18 will introduce stricter actions against smurfing
Dev Update
Xin Zhao Visual Update

Doom Bots
Wukong Bot Example:
Veigar (boss) will interact with the other doombots after 15 minutes
Trials of Doom introduced as a new difficulty challenge that gives all the doom bots more power
Read the full list of changes here
Smurfing Penalties
You can read Riot's full thoughts on what constitutes as smurfing or not here. The TLDR is this:
Accounts that have been bought or botted will be hit the hardest
Ranking up on an account that is not your own will be punished
Queuing with another account (typically a booster) in order to get carried to a higher division than you deserve will be punished
Leveling up your own account to play with lesser skilled friends is still okay
Riot is working on ways to more accurately place new accounts into the appropriate rank