1) I'm pretty sure a final cure for HIV-1 and better detection + treatment for AIDS will come up in the next 4 years. Also, the Pre and Post exposure drugs will probably become efficient for infections older than 48 hours. The things with HIV/AIDS research is that a discovery on one end of the disease yields results on all of them in a short amount of time.
2) Populism and nationalism will start to die out because gen X and Z are brought up in a more data-available world. They'll probably have a more Hans Rosling/Steven Pinker attitude towards the world than a Trump/Johnson one.
3) Ethiopia will become the powerhouse of the continent, prompting migration from all over. If an open and/or tolerant attitude is kept towards neighbors, it might generate a ripple effect across the whole region - an effect consisting in stability. That's what Israel could've done if a dual-state solution was obtained, or Iran if the CIA hadn't generate a coup to remove the democratic prime minister because BP Oil couldn't buy cheap resources anymore. I really hope no one fucks up this time.
4) Poorer countries will outpace the more developed ones in terms of digital governance, administration and bureaucracy since they'll start implement administrative reforms with the current available tools that have the power to reach anyone - which are all online. Current administrations from developed countries still need to overcome the integration nightmare of current systems.
5) Public photography and filming will get intensely regulated worldwide as the laws haven't been adapted to the smartphone era as well as the digital privacy era. For example: currently, photographers are allowed to snap photos of you in public without asking for consent in most of the countries. Then they sell them off for 100 dollars on Getty Images. Then you see yourself in a prostate ad from an obscure magazine sold in a mall in Indiana. Life's complicated.