Crack on exterior of house--is this a concern?

[Bienes Raices]

I noticed this stair-shaped crack recently at the concrete block rental house. I don't see any warning signs of sinkhole activity around or inside the house. I tried to stick a credit card in the gap and it wouldn't fit, so the crack is very thin at this point. Should I just put some clear caulk over it to prevent water intrusion or could this be a sign of a more serious issue? The house was built about 20 years ago.