No tenant may sublet an apartment without the written consent of the landlord. If you did not consent to the sublease then it is not valid or enforceable. Your remedy is to terminate your tenant's lease, which will also terminate any subleases.
A sublease contract means less control over apartment changes. As a subtenant, you have limited control over the apartment as you are not the primary leaseholder. The original tenant has ultimate control over the property and can impose restrictions or limitations on your use of the space.
Subletting. In Texas, you are not allowed to rent your place to someone else without your landlord's permission. This law is in Section 91.005 of Texas Property Code. Some leases may allow it under certain conditions.
San Francisco, Oakland and Berkeley passed laws to protect renters in roommate/subletting situations. If you live in one of these cities, your landlord can neither deny you the right to nor evict you for replacing a roommate or subletting a room without their consent.
Reasons a landlord might deny a sublet request Allowing the sublet would result in too many people living in the unit. Too many residents would be under 18. The prospective subtenant won't agree to the same terms as the original rental agreement. The prospective subtenant plans to keep pets in the unit.
Cons of Subleasing Not all subleasers are dependable; sometimes, they sublet because they can't make ends meet, which can be an issue. Although the original tenant is financially responsible, that doesn't remove all risk for landlords.
Too much trouble and risk if things go wrong. Makes evictions more complicated and costly. especially in a tenant friendly state like CA. All pain, for no gain.