The block subsidy cuts in half. Every 10min there is 6.25BTC awarded as a subsidy to the miner that finds the nonce which provides enough leading zeros (difficulty number that adjusts every 2016 blocks or about two weeks) when hashed using SHA256 with the previous block hash and all transactions in the block template (crafted from the mempool aka awaiting transactions). This 6.25BTC subsidy amount plus transaction fees from the block template make up the total block reward. After the next halving, the subsidy will be cut in half (using bit shift based on the number of epochs aka halvings) so will only be 3.125BTC. This halving happens ever 210k blocks or roughly every four years calendar time.

2008 - 50 BTC/block

2012 - 25 BTC/block

2016 - 12.5 BTC/block

2020 - 6.25 BTC/block

2024 - 3.125 BTC/block

2028 - 1.5625 BTC/block

And so on until about 2140 or so.