They both are spending tons of money to spread propaganda to influence public opinion and elections is the first and easiest to point out.
They also both own major news outlets that defend them publicly and are very influential of public opinion.
Both have through their businesses received government subsidies, in effect having us tax dollars go to their pockets. This cycle is repeated through the influence they buy by spreading propaganda, using lobbyists, using money as a tool within the government apparatus to generate more money for their companies and in turn for themselves.