The former is that your patent right is completely lost and given to others; The latter is that you give a part of the patent right to others and get it back when it expires.
(1) Patent licensing, also known as patent licensing trade, refers to that the owner of patented technology or its authorized person permits others to exploit the patent in a certain way within a certain period of time and in a certain area, and collects royalties from others. Patent license only transfers the right to use the patented technology, the transferor still owns the patent, and the transferee only has the right to exploit the patented technology, but not the patent ownership. Patent licensing is a kind of licensing trade that allows licensees to use their patents within a certain range by concluding a patent licensing contract and paying royalties.
(2) Patent assignment refers to a contract in which the patentee, as the assignor, transfers the ownership or holding right of his invention-creation patent to the assignee, and the assignee pays the agreed price. The party who obtains the patent right through the patent right transfer contract becomes a new legal patentee, and may also conclude a patent transfer contract, a patent licensing contract and a patent application right transfer contract with others.