According to
https://www.popsci.com/should-we-send-men-venus-instead-mars , the next manned space mission should be to Venus because is almost like earth in regards to the amount of sunlight, temperature, gravity, and the gases' altitude being able to support life. Unfortunately, Venus was described as "hellish and unwelcoming" due to its atmosphere. According to
https://www.nasa.gov/vision/universe/solarsystem/mars_challenges.html , Landing on mars has its challenges when considering landing on the planet. The first reason of difficulty is simply described, "Getting to Mars is hard", because of where you actually have to land due to the depth of mars into the solar system. The environment is hazardous and the risks of landing on mars seem much more intense than landing on Venus.