Steering wheel leans slightly to the left?

Take it back to the shop that did the alignment. They should correct that at no charge.

There are three primary alignment angles to adjust. The last ones are "toe" on each front wheel. That is the direction the wheels are steering when the steering wheel is perfectly straight. Toe is adjusted at the connection between the inner and outer tie rod ends.

Normal procedure is to hold or lock the steering wheel perfectly straight, then adjust each front wheel to bring it also straight. That sounds like a simple procedure, and on most models it is, but there are a few on which that never worked for me. The tires sit on sliding turntables that must be free to move around. A little sand or dirt in them can cause them to not rotate the tiny amount needed to show up on the computer screen. Some models have normal play in the steering shaft and linkage. A lot of models with power steering have excessive free play in the gear boxes when the engine is not running. There were some truck models that I knew would not end up with a straight steering wheel, so I took some wrenches with me on the test drive, and stopped to make adjustments on the side of the road when necessary.

There's two ways to set toe, depending on the design of the steering system. On almost all car models, once the steering wheel is locked straight ahead, the left wheel is adjusted to specs, then the right one is adjusted. Specs usually calls for a little "toe-in", meaning the fronts of the wheels are closer together, by about 1/8th inch, than the rears of those tires. Road forces tug them straight and parallel while driving.

In the second design, often found on trucks, total toe is adjusted to specs through just one adjuster. Next, a different adjuster in the steering linkage only affects the position of the steering wheel, nothing else. Those are the ones that can be adjusted on the side of the road without affecting anything that involves tire wear or pulling to one side.

Most alignment specialists have a preferred route they use for test drives to verify there's no pull and the steering wheel is straight. However, I have known a few specialists who don't bother with a test drive. They get more customer complaints but they spend less time on each vehicle.

It's also important to understand the difference between a pull and an off-center steering wheel. When you let go of the steering wheel at highway speed, the vehicle should go straight for at least one or two tenths of a mile If it does, but the steering wheel is off-center, that requires readjustment of toe on each front wheel. On the other hand, if the car does constantly creep to one side, and you have to bring it back into your lane by turning the steering wheel, that is a pull. The steering wheel may or may not be centered, but you can't know until the pull is corrected.

Many mechanics make printouts of the alignment. I always put a copy on the passenger seat, with everything I adjusted highlighted. The screen I preferred showed the "Before" readings, meaning what the car came in with, and the "After" readings that showed the numbers after I was done with the alignment. If you got such a printout, and if you can post it, I will interpret the numbers for you.