Can CB radio communicate with PMR?

No, CB radio and PMR446 generally cannot communicate directly with each other. CB radio (Citizen Band Radio) operates on frequencies in the 27 MHz band, while PMR446 (Private Mobile Radio 446) is used on frequencies around 446 MHz. Both services use different frequency ranges and have different technical standards, which precludes direct communication between the two systems. In order to communicate between the two radio services, some type of crossband repeater or similar technical solution would have to be used, although this is not permitted by law in many countries.