Chip and signature, which often means just the chip without further authentication.

EMV has multiple options. Many countries (including the US) chose the signature option for credit cards for convenience and use PINs only with debit cards. Before contactless payment apps became common, that was a major source of friction when using American credit cards in Europe.

I'd argue we picked it for legacy reasons - Americans are not used to the chip/pin concept, and adopted EMV very late because of a variety of legacy reasons (massive installed base of mag stripe equipment, and systems to deal with the inherent slightly higher fraud).