I started leasing a car for work in 2018. My amount due at lease signing was $5544. Is that deductible?

The rules for deducting the costs of a leased vehicle as a business expense are very specific.  I suggest your review the Car Expenses section under Transportation in this IRS publication: https://www.irs.gov/publications/p463

For some general information, see this TurboTax article: https://turbotax.intuit.com/tax-tips/small-business-taxes/business-use-of-vehicles/L6hi0zzzh