Aphids, been dealing with some on my pepper plants here lately.
Smush em with your fingers by gently squeezing, rubbing the leaves.
Or blast them off with the garden hose.
Or go gather up lady bugs and place them on the piles of aphids lol.
Neem oil is supposed to work- I just bought some to try for another option to keep them in check- today is the first day Ive used it, so will see.