What is the block reward, and how does it incentivize miners?

The block reward is freshly created cryptocurrency the protocol pays to whoever produces a valid block; together with transaction fees, it is what makes mining profitable.

A block producer earns money in two ways: the transaction fees from the transactions they include, and a block reward minted by the protocol itself and handed to them for successfully adding a block. The reward is what motivates people to spend electricity and hardware securing the network — without a payoff, nobody would do the costly work. The block reward also controls how new coins enter circulation. Many chains taper it over time: Bitcoin's reward is cut in half roughly every four years (the "halving"), and some chains eventually stop issuing rewards entirely, leaving miners paid purely by transaction fees. The incentive design is the whole point — honest block production is the most profitable strategy, so rational participants secure the chain by pursuing their own gain.

Go deeper:

• Bitcoin — Wikipedia — the block subsidy, the roughly four-year "halving," and the shift toward fee-only rewards.