The First BTC Halving
Crypto community witnessed first Bitcoin halving in November 2012
Miners got 50 BTC per block when Bitcoin was released in 2009. In 2012 this figure was decreased to 25 BTC per mining block
So after first halving the number of BTC was halved.
The tentative year for last BTC halving is 2140 and total BTC mined will be 21 millions and after it no BTC coin will be mined. After it miners will get only gas fees.
After the full BTC quantity is mines miners will have to transfer the transaction processing system to some other crypto and the scarcity of BTC may increase its value manifold.
With decrease in BTC mining reward, lowered supply increases BTC demand and hence increase in BTC price.