Folding @ Home is an easy way to assist in medical research - you leave the program running in the background and it uses your idle processing power to run complex simulations, speeding up the research process by spreading out the technical workload. As you run it, you gather "points", which you can contribute towards a team.
Currently the biggest section of research is for fighting COVID-19/coronavirus (set it to "Any disease" and for the time being it will do COVID automatically).