The RP2040 is the CPU in the Raspberry Pi Pico. Adafruit have released an RP2040-based board in the "Itsy Bitsy" form factor, call the Itsy Bitsy RP2040. It can be programmed in C/C++ like an Arduino, or in CircuitPython or MicroPython.
MicroPython Examples, examples to accompany the "Raspberry Pi Pico Python SDK "
book published by Raspberry Pi Trading, which forms part of the technical documentation in support of Raspberry Pi Pico and the MicroPython port to RP2040.