The kung fu masters value honesty, teamwork, patience, forgiveness, and loyalty, and positive qualities like these are central to the characters' ability to weather storms and defeat evildoers. Po isn't a traditional Dragon Warrior, but he uses his strengths -- including creative problem solving and a positive attitude -- to compensate for what he lacks. Villains are no match for the kung fu masters, and good always prevails over evil.
Martial arts-style combat is common both in training scenes and in the protagonists' face-offs with villains. Machines play a role in the fighting at times, which ups the intensity but never really hurts the characters. Mild peril and verbal threats of harm and implied death may be too much for very young viewers.
Some talk about boyfriends and girlfriends.
Characters call each other names like "moron" and use "butt" infrequently.
This series is intertwined with a marketing franchise that includes multiple movies, TV specials, video games, and just about every accessory/product tie-in you can think of.