The general term for modem is modulator-demodulator, so on a basic level they do. However,  purchasing the wrong modem can limit the speed of your network because ISP’s have different speed tiers and not all modems are rated to work with all speed tiers. So, it is recommended to check out your ISP’s approved modem list to see what speed tiers the modem your interested in is rated for. 

going off what @Where the Wild Pings Are said, I’d also watch for docsis 3.1 devices. Many of the isp’s are dropping the speed tiers of what docsis 3.0 devices support. So even if a docsis 3.0 device currently supports your speeds, if the ISP drops their support speed for it, you’d need to upgrade. so if you’re debating on it, its better to go with a little more capabilities versus “just enough” if its the difference from 3.1 to 3.0.