How Does the Expiration Date Affect the Pricing of a Futures Contract?

The expiration date is a key determinant of the contract price, primarily through the cost of carry. The longer the time to expiration, the greater the potential impact of interest rates and storage costs (or funding rates in crypto) on the price, leading to a difference between the futures price and the current spot price.

This difference is the "basis."

How Does the Expiration Date of a Futures Contract Influence Its Price?
How Is the Cost of Carry Concept Adapted for Non-Storable Assets like Cryptocurrencies?
How Is the ‘Cost of Carry’ Calculated for a Physical Commodity versus a Financial Future?
What Is the Primary Difference between the Cost of Carry for Gold and the Cost of Carry for Bitcoin?
Define “Cost of Carry” in the Context of Futures Pricing
How Do ‘Storage Costs’ Affect the Relationship between Futures and Spot Prices?
How Does the Cost of Carry for a Commodity Differ from That of a Cryptocurrency, and How Does This Impact Option Style?
How Does the Concept of “Negative Carry” Apply to a Cash-and-Carry Trade in a Negative Interest Rate Environment?