On April Fifth, Wisconsin held its primaries. In the Democratic Party, Sanders beat Clinton by 13.5 points, although Clinton is still winning the democratic nominee with seven hundred delegates. In the Republican Party, Cruz got first by 13.1 points on Trump, boosting him to only two hundred delegates behind Trump.
In Republican Party there is now a very strong chance of a contested convention. A contested convention happens when none of the delegates have a majority. The delegates are released from their votes and they can go vote for whomever they want. This will keep going until someone has a majority vote. The last time the Republican party had a contested nomination was 1976. The last time a contested convention led to a winning president was 1932, when Franklin Roosevelt won presidency.