Personally, I think the landlord can wear black slacks with this black sweater.
Both black and gray khaki can go with this black one.
Sweater but I personally think khaki slacks look best with this black sweater.
It looks very foreign, handsome and cool.
It looks much better with this pair than gray-black slacks.
It is recommended that the landlord match white sneakers or sports casual shoes.
The color of shoes is suggested to be white, beige and gray, because the upper body dress of the landlord is dark.
Then choosing the color of shoes can brighten the overall effect.
I suggest the landlord try it.
This overall collocation is very handsome and sunny.
Finally, I hope the above suggestions can help the landlord!