Lat pulldowns, inverted rows, band-assisted pull-ups, and single-arm dumbbell rows all cover the same vertical and back pulling.
If you cannot do pull-ups or lack a bar, the closest replacements are the lat pulldown for the same vertical pulling pattern, and inverted rows under a bar or table for horizontal back work. Band-assisted or machine-assisted pull-ups let you train the exact movement while building up to a bodyweight rep. Single-arm dumbbell rows and dumbbell pullovers cover the lats when you only have dumbbells.
The pulldown trains the same overhead pulling pattern and lat emphasis as a pull-up, just with adjustable load. It is ideal if pull-ups are too hard, because you can pick a weight that lets you train in a productive rep range.
Band-assisted pull-ups, assisted pull-up machines, and slow negatives from the top let you train the actual movement while removing some of your bodyweight. These are the fastest path to your first strict pull-up.
With no bar or cable, inverted rows using a bar, rings, or a sturdy table hit the back through a horizontal pull. Single-arm dumbbell rows and dumbbell pullovers add lat work, and a doorway or resistance band can mimic straight-arm pulldowns.
Lat pulldowns, inverted rows, band-assisted pull-ups, and single-arm dumbbell rows all cover the same vertical and back pulling.
